Code clean-up thanks to SonarLint & bugfix for ByteArray::compareTo!

src/main/java/org/hsqldb/jdbc/HSQLDBPool.java

@@ -3,7 +3,6 @@ package org.hsqldb.jdbc;
 import java.sql.Connection;
 import java.sql.SQLException;
 
-import org.hsqldb.jdbc.JDBCPool;
 import org.hsqldb.jdbc.pool.JDBCPooledConnection;
 
 public class HSQLDBPool extends JDBCPool {

src/main/java/org/qora/ApplyUpdate.java

@@ -34,10 +34,10 @@ public class ApplyUpdate {
 	private static final String NEW_JAR_FILENAME = AutoUpdate.NEW_JAR_FILENAME;
 	private static final String WINDOWS_EXE_LAUNCHER = "qora-core.exe";
 
-	private static final long CHECK_INTERVAL = 5 * 1000; // ms
+	private static final long CHECK_INTERVAL = 5 * 1000L; // ms
 	private static final int MAX_ATTEMPTS = 5;
 
-	public static void main(String args[]) {
+	public static void main(String[] args) {
 		Security.insertProviderAt(new BouncyCastleProvider(), 0);
 		Security.insertProviderAt(new BouncyCastleJsseProvider(), 1);
 
@@ -114,6 +114,7 @@ public class ApplyUpdate {
 			try {
 				Thread.sleep(CHECK_INTERVAL);
 			} catch (InterruptedException e) {
+				// Doggedly retry
 			}
 		}
 

src/main/java/org/qora/ProxyKeys.java

@@ -1,6 +1,5 @@
 package org.qora;
 
-import java.io.IOException;
 import java.security.Security;
 
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
@@ -17,15 +16,15 @@ public class ProxyKeys {
 		System.exit(1);
 	}
 
-	public static void main(String argv[]) throws IOException {
-		if (argv.length != 2)
+	public static void main(String[] args) {
+		if (args.length != 2)
 			usage();
 
 		Security.insertProviderAt(new BouncyCastleProvider(), 0);
 		Security.insertProviderAt(new BouncyCastleJsseProvider(), 1);
 
-		PrivateKeyAccount privateAccount = new PrivateKeyAccount(null, Base58.decode(argv[0]));
-		PublicKeyAccount publicAccount = new PublicKeyAccount(null, Base58.decode(argv[1]));
+		PrivateKeyAccount privateAccount = new PrivateKeyAccount(null, Base58.decode(args[0]));
+		PublicKeyAccount publicAccount = new PublicKeyAccount(null, Base58.decode(args[1]));
 
 		byte[] proxyPrivateKey = privateAccount.getProxyPrivateKey(publicAccount.getPublicKey());
 

src/main/java/org/qora/VanityGen.java

@@ -1,6 +1,5 @@
 package org.qora;
 
-import java.io.IOException;
 import java.security.SecureRandom;
 import java.security.Security;
 import java.util.Random;
@@ -59,22 +58,22 @@ public class VanityGen {
 		}
 	}
 
-	public static void main(String argv[]) throws IOException {
-		if (argv.length == 0)
+	public static void main(String[] args) {
+		if (args.length == 0)
 			usage();
 
 		int threadCount = 1;
 
 		int argIndex = 0;
-		while (argIndex < argv.length) {
-			String arg = argv[argIndex++];
+		while (argIndex < args.length) {
+			String arg = args[argIndex++];
 
 			if (arg.equals("-t")) {
-				if (argIndex >= argv.length)
+				if (argIndex >= args.length)
 					usage();
 
 				try {
-					threadCount = Integer.parseInt(argv[argIndex++]);
+					threadCount = Integer.parseInt(args[argIndex++]);
 				} catch (NumberFormatException e) {
 					usage();
 				}

src/main/java/org/qora/XorUpdate.java

@@ -13,7 +13,7 @@ public class XorUpdate {
 
 	private static final byte XOR_VALUE = AutoUpdate.XOR_VALUE;
 
-	public static void main(String args[]) {
+	public static void main(String[] args) {
 		if (args.length != 2) {
 			System.err.println("usage: XorUpdate <input-file> <output-file>");
 			System.exit(1);

src/main/java/org/qora/account/Account.java

@@ -142,9 +142,9 @@ public class Account {
 		byte[] reference = null;
 
 		for (TransactionData transactionData : unconfirmedTransactions) {
-			String address = PublicKeyAccount.getAddress(transactionData.getCreatorPublicKey());
+			String unconfirmedTransactionAddress = PublicKeyAccount.getAddress(transactionData.getCreatorPublicKey());
 
-			if (address.equals(this.address))
+			if (unconfirmedTransactionAddress.equals(this.address))
 				reference = transactionData.getSignature();
 		}
 

src/main/java/org/qora/api/ApiError.java

@@ -118,7 +118,7 @@ public enum ApiError {
 	// Groups
 	GROUP_UNKNOWN(1101, 404);
 
-	private final static Map<Integer, ApiError> map = stream(ApiError.values()).collect(toMap(apiError -> apiError.code, apiError -> apiError));
+	private static final Map<Integer, ApiError> map = stream(ApiError.values()).collect(toMap(apiError -> apiError.code, apiError -> apiError));
 
 	private final int code; // API error code
 	private final int status; // HTTP status code

src/main/java/org/qora/api/ApiException.java

@@ -10,12 +10,12 @@ public class ApiException extends WebApplicationException {
 	private static final long serialVersionUID = 4619299036312089050L;
 
 	// HTTP status code
-	public int status;
+	public final int status;
 
 	// API error code
-	public int error;
+	public final int error;
 
-	public String message;
+	public final String message;
 
 	public ApiException(int status, int error, String message) {
 		this(status, error, message, null);

src/main/java/org/qora/api/ApiService.java

@@ -47,7 +47,6 @@ public class ApiService {
 	}
 
 	public Iterable<Class<?>> getResources() {
-		// return resources;
 		return this.config.getClasses();
 	}
 

src/main/java/org/qora/api/TransactionCountMapXmlAdapter.java

@@ -1,7 +1,7 @@
 package org.qora.api;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -17,7 +17,7 @@ public class TransactionCountMapXmlAdapter extends XmlAdapter<TransactionCountMa
 
 	public static class StringIntegerMap {
 		@XmlVariableNode("key")
-		List<MapEntry> entries = new ArrayList<MapEntry>();
+		List<MapEntry> entries = new ArrayList<>();
 	}
 
 	public static class MapEntry {
@@ -30,7 +30,7 @@ public class TransactionCountMapXmlAdapter extends XmlAdapter<TransactionCountMa
 
 	@Override
 	public Map<TransactionType, Integer> unmarshal(StringIntegerMap stringIntegerMap) throws Exception {
-		Map<TransactionType, Integer> map = new HashMap<>(stringIntegerMap.entries.size());
+		Map<TransactionType, Integer> map = new EnumMap<>(TransactionType.class);
 
 		for (MapEntry entry : stringIntegerMap.entries)
 			map.put(TransactionType.valueOf(entry.key), entry.value);

src/main/java/org/qora/api/model/ActivitySummary.java

@@ -1,6 +1,6 @@
 package org.qora.api.model;
 
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.Map;
 
 import javax.xml.bind.annotation.XmlAccessType;
@@ -20,9 +20,10 @@ public class ActivitySummary {
 
 	// Assuming TransactionType values are contiguous so 'length' equals count
 	@XmlJavaTypeAdapter(TransactionCountMapXmlAdapter.class)
-	public Map<TransactionType, Integer> transactionCountByType = new HashMap<>();
+	public Map<TransactionType, Integer> transactionCountByType = new EnumMap<>(TransactionType.class);
 
 	public ActivitySummary() {
+		// Needed for JAXB
 	}
 
 }

src/main/java/org/qora/api/resource/AddressesResource.java

@@ -30,7 +30,6 @@ import org.qora.api.ApiException;
 import org.qora.api.ApiExceptionFactory;
 import org.qora.api.model.ApiOnlineAccount;
 import org.qora.api.model.ProxyKeyRequest;
-import org.qora.api.resource.TransactionsResource;
 import org.qora.asset.Asset;
 import org.qora.controller.Controller;
 import org.qora.crypto.Crypto;

src/main/java/org/qora/api/resource/AdminResource.java

@@ -134,18 +134,15 @@ public class AdminResource {
 	public String shutdown() {
 		Security.checkApiCallAllowed(request);
 
-		new Thread(new Runnable() {
-			@Override
-			public void run() {
-				// Short sleep to allow HTTP response body to be emitted
-				try {
-					Thread.sleep(1000);
-				} catch (InterruptedException e) {
-					// Not important
-				}
-
-				Controller.getInstance().shutdownAndExit();
+		new Thread(() -> {
+			// Short sleep to allow HTTP response body to be emitted
+			try {
+				Thread.sleep(1000);
+			} catch (InterruptedException e) {
+				// Not important
 			}
+
+			Controller.getInstance().shutdownAndExit();
 		}).start();
 
 		return "true";

src/main/java/org/qora/api/resource/AnnotationPostProcessor.java

@@ -66,7 +66,7 @@ public class AnnotationPostProcessor implements ReaderListener {
 				if (apiErrors == null)
 					continue;
 
-				LOGGER.trace("Found @ApiErrors annotation on " + clazz.getSimpleName() + "." + method.getName());
+				LOGGER.trace(() -> String.format("Found @ApiErrors annotation on %s.%s", clazz.getSimpleName(), method.getName()));
 				PathItem pathItem = getPathItemFromMethod(openAPI, classPathString, method);
 
 				if (pathItem == null) {

src/main/java/org/qora/api/resource/AssetsResource.java

@@ -282,7 +282,7 @@ public class AssetsResource {
 			List<OrderData> orders = repository.getAssetRepository().getAggregatedOpenOrders(assetId, otherAssetId, limit, offset, reverse);
 
 			// Map to aggregated form
-			return orders.stream().map(orderData -> new AggregatedOrder(orderData)).collect(Collectors.toList());
+			return orders.stream().map(AggregatedOrder::new).collect(Collectors.toList());
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}

src/main/java/org/qora/api/resource/GroupsResource.java

@@ -98,9 +98,7 @@ public class GroupsResource {
 		ref = "reverse"
 	) @QueryParam("reverse") Boolean reverse) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<GroupData> groups = repository.getGroupRepository().getAllGroups(limit, offset, reverse);
-
-			return groups;
+			return repository.getGroupRepository().getAllGroups(limit, offset, reverse);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -126,9 +124,7 @@ public class GroupsResource {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<GroupData> groups = repository.getGroupRepository().getGroupsByOwner(owner);
-
-			return groups;
+			return repository.getGroupRepository().getGroupsByOwner(owner);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -154,9 +150,7 @@ public class GroupsResource {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<GroupData> groups = repository.getGroupRepository().getGroupsWithMember(member);
-
-			return groups;
+			return repository.getGroupRepository().getGroupsWithMember(member);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}

src/main/java/org/qora/api/resource/NamesResource.java

@@ -73,7 +73,7 @@ public class NamesResource {
 			List<NameData> names = repository.getNameRepository().getAllNames(limit, offset, reverse);
 
 			// Convert to summary
-			return names.stream().map(nameData -> new NameSummary(nameData)).collect(Collectors.toList());
+			return names.stream().map(NameSummary::new).collect(Collectors.toList());
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -102,7 +102,7 @@ public class NamesResource {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			List<NameData> names = repository.getNameRepository().getNamesByOwner(address, limit, offset, reverse);
 
-			return names.stream().map(nameData -> new NameSummary(nameData)).collect(Collectors.toList());
+			return names.stream().map(NameSummary::new).collect(Collectors.toList());
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}

src/main/java/org/qora/api/resource/PeersResource.java

@@ -56,7 +56,7 @@ public class PeersResource {
 		}
 	)
 	public List<ConnectedPeer> getPeers() {
-		return Network.getInstance().getConnectedPeers().stream().map(peer -> new ConnectedPeer(peer)).collect(Collectors.toList());
+		return Network.getInstance().getConnectedPeers().stream().map(ConnectedPeer::new).collect(Collectors.toList());
 	}
 
 	@GET

src/main/java/org/qora/api/resource/TransactionsResource.java

@@ -311,7 +311,7 @@ public class TransactionsResource {
 					txTypes, null, address, confirmationStatus, limit, offset, reverse);
 
 			// Expand signatures to transactions
-			List<TransactionData> transactions = new ArrayList<TransactionData>(signatures.size());
+			List<TransactionData> transactions = new ArrayList<>(signatures.size());
 			for (byte[] signature : signatures)
 				transactions.add(repository.getTransactionRepository().fromSignature(signature));
 

src/main/java/org/qora/asset/Order.java

@@ -229,14 +229,15 @@ public class Order {
 
 		final boolean isOrderNewAssetPricing = orderData.getTimestamp() >= BlockChain.getInstance().getNewAssetPricingTimestamp();
 
-		final long haveAssetId = orderData.getHaveAssetId();
-		final long wantAssetId = orderData.getWantAssetId();
+		// Cached for readability
+		final long _haveAssetId = orderData.getHaveAssetId();
+		final long _wantAssetId = orderData.getWantAssetId();
 
-		final AssetData haveAssetData = this.repository.getAssetRepository().fromAssetId(haveAssetId);
-		final AssetData wantAssetData = this.repository.getAssetRepository().fromAssetId(wantAssetId);
+		final AssetData haveAssetData = this.repository.getAssetRepository().fromAssetId(_haveAssetId);
+		final AssetData wantAssetData = this.repository.getAssetRepository().fromAssetId(_wantAssetId);
 
-		final long amountAssetId = (isOurOrderNewPricing && wantAssetId > haveAssetId) ? wantAssetId : haveAssetId;
-		final long returnAssetId = (isOurOrderNewPricing && haveAssetId < wantAssetId) ? haveAssetId : wantAssetId;
+		final long amountAssetId = (isOurOrderNewPricing && _wantAssetId > _haveAssetId) ? _wantAssetId : _haveAssetId;
+		final long returnAssetId = (isOurOrderNewPricing && _haveAssetId < _wantAssetId) ? _haveAssetId : _wantAssetId;
 
 		final AssetData amountAssetData = this.repository.getAssetRepository().fromAssetId(amountAssetId);
 		final AssetData returnAssetData = this.repository.getAssetRepository().fromAssetId(returnAssetId);

src/main/java/org/qora/at/AT.java

@@ -45,7 +45,7 @@ public class AT {
 
 		byte[] creationBytes = deployATTransactionData.getCreationBytes();
 		long assetId = deployATTransactionData.getAssetId();
-		short version = (short) (creationBytes[0] | (creationBytes[1] << 8)); // Little-endian
+		short version = (short) ((creationBytes[0] & 0xff) | (creationBytes[1] << 8)); // Little-endian
 
 		if (version >= 2) {
 			MachineState machineState = new MachineState(deployATTransactionData.getCreationBytes());
@@ -78,7 +78,7 @@ public class AT {
 
 			// Extract actual code length, stored in minimal-size form (byte, short or int)
 			if (numCodePages * 256 < 257) {
-				codeLen = (int) (byteBuffer.get() & 0xff);
+				codeLen = byteBuffer.get() & 0xff;
 			} else if (numCodePages * 256 < Short.MAX_VALUE + 1) {
 				codeLen = byteBuffer.getShort() & 0xffff;
 			} else if (numCodePages * 256 <= Integer.MAX_VALUE) {
@@ -135,14 +135,14 @@ public class AT {
 		byte[] codeBytes = this.atData.getCodeBytes();
 
 		// Fetch latest ATStateData for this AT (if any)
-		ATStateData atStateData = this.repository.getATRepository().getLatestATState(atAddress);
+		ATStateData latestAtStateData = this.repository.getATRepository().getLatestATState(atAddress);
 
 		// There should be at least initial AT state data
-		if (atStateData == null)
+		if (latestAtStateData == null)
 			throw new IllegalStateException("No initial AT state data found");
 
 		// [Re]create AT machine state using AT state data or from scratch as applicable
-		MachineState state = MachineState.fromBytes(api, logger, atStateData.getStateData(), codeBytes);
+		MachineState state = MachineState.fromBytes(api, logger, latestAtStateData.getStateData(), codeBytes);
 		state.execute();
 
 		int height = this.repository.getBlockRepository().getBlockchainHeight() + 1;

src/main/java/org/qora/at/BlockchainAPI.java

@@ -115,7 +115,7 @@ public enum BlockchainAPI {
 
 	public final int value;
 
-	private final static Map<Integer, BlockchainAPI> map = stream(BlockchainAPI.values()).collect(toMap(type -> type.value, type -> type));
+	private static final Map<Integer, BlockchainAPI> map = stream(BlockchainAPI.values()).collect(toMap(type -> type.value, type -> type));
 
 	BlockchainAPI(int value) {
 		this.value = value;

src/main/java/org/qora/at/QoraATAPI.java

@@ -52,7 +52,7 @@ public class QoraATAPI extends API {
 	public QoraATAPI(Repository repository, ATData atData, long blockTimestamp) {
 		this.repository = repository;
 		this.atData = atData;
-		this.transactions = new ArrayList<AtTransaction>();
+		this.transactions = new ArrayList<>();
 		this.blockTimestamp = blockTimestamp;
 	}
 

src/main/java/org/qora/at/QoraATLogger.java

@@ -2,7 +2,6 @@ package org.qora.at;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.qora.at.AT;
 
 public class QoraATLogger implements org.ciyam.at.LoggerInterface {
 

src/main/java/org/qora/at/QoraFunctionCode.java

@@ -1,6 +1,6 @@
 package org.qora.at;
 
-import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -37,14 +37,10 @@ public enum QoraFunctionCode {
 		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
 			Timestamp timestamp = new Timestamp(functionData.value2);
 
-			try {
-				String recipient = new String(state.getB(), "UTF-8");
+			String recipient = new String(state.getB(), StandardCharsets.UTF_8);
 
-				BlockchainAPI blockchainAPI = BlockchainAPI.valueOf(timestamp.blockchainId);
-				blockchainAPI.putTransactionFromRecipientAfterTimestampInA(recipient, timestamp, state);
-			} catch (UnsupportedEncodingException e) {
-				throw new ExecutionException("Couldn't parse recipient from B", e);
-			}
+			BlockchainAPI blockchainAPI = BlockchainAPI.valueOf(timestamp.blockchainId);
+			blockchainAPI.putTransactionFromRecipientAfterTimestampInA(recipient, timestamp, state);
 		}
 	};
 
@@ -102,6 +98,6 @@ public enum QoraFunctionCode {
 	}
 
 	/** Actually execute function */
-	abstract protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException;
+	protected abstract void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException;
 
 }

src/main/java/org/qora/block/BlockGenerator.java

@@ -2,6 +2,7 @@ package org.qora.block;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.locks.ReentrantLock;
@@ -204,7 +205,7 @@ public class BlockGenerator extends Thread {
 					ValidationResult validationResult = newBlock.isValid();
 					if (validationResult != ValidationResult.OK) {
 						// No longer valid? Report and discard
-						LOGGER.error("Valid, generated block now invalid '" + validationResult.name() + "' after adding unconfirmed transactions?");
+						LOGGER.error(String.format("Valid, generated block now invalid '%s' after adding unconfirmed transactions?", validationResult.name()));
 
 						// Rebuild block candidates, just to be sure
 						newBlocks.clear();
@@ -215,7 +216,7 @@ public class BlockGenerator extends Thread {
 					try {
 						newBlock.process();
 
-						LOGGER.info("Generated new block: " + newBlock.getBlockData().getHeight());
+						LOGGER.info(String.format("Generated new block: %d", newBlock.getBlockData().getHeight()));
 						repository.saveChanges();
 
 						ProxyForgerData proxyForgerData = repository.getAccountRepository().getProxyForgeData(newBlock.getBlockData().getGeneratorPublicKey());
@@ -292,24 +293,15 @@ public class BlockGenerator extends Thread {
 		// Grab all valid unconfirmed transactions (already sorted)
 		List<TransactionData> unconfirmedTransactions = Transaction.getUnconfirmedTransactions(repository);
 
-		for (int i = 0; i < unconfirmedTransactions.size(); ++i) {
-			TransactionData transactionData = unconfirmedTransactions.get(i);
+		Iterator<TransactionData> unconfirmedTransactionsIterator = unconfirmedTransactions.iterator();
+		final long newBlockTimestamp = newBlock.getBlockData().getTimestamp();
+		while (unconfirmedTransactionsIterator.hasNext()) {
+			TransactionData transactionData = unconfirmedTransactionsIterator.next();
 
 			// Ignore transactions that have timestamp later than block's timestamp (not yet valid)
-			if (transactionData.getTimestamp() > newBlock.getBlockData().getTimestamp()) {
-				unconfirmedTransactions.remove(i);
-				--i;
-				continue;
-			}
-
-			Transaction transaction = Transaction.fromData(repository, transactionData);
-
 			// Ignore transactions that have expired before this block - they will be cleaned up later
-			if (transaction.getDeadline() <= newBlock.getBlockData().getTimestamp()) {
-				unconfirmedTransactions.remove(i);
-				--i;
-				continue;
-			}
+			if (transactionData.getTimestamp() > newBlockTimestamp || Transaction.getDeadline(transactionData) <= newBlockTimestamp)
+				unconfirmedTransactionsIterator.remove();
 		}
 
 		// Sign to create block's signature, needed by Block.isValid()
@@ -324,7 +316,7 @@ public class BlockGenerator extends Thread {
 			// If newBlock is no longer valid then we can't use transaction
 			ValidationResult validationResult = newBlock.isValid();
 			if (validationResult != ValidationResult.OK) {
-				LOGGER.debug("Skipping invalid transaction " + Base58.encode(transactionData.getSignature()) + " during block generation");
+				LOGGER.debug(() -> String.format("Skipping invalid transaction %s during block generation", Base58.encode(transactionData.getSignature())));
 				newBlock.deleteTransaction(transactionData);
 			}
 		}

src/main/java/org/qora/block/GenesisBlock.java

@@ -54,7 +54,7 @@ public class GenesisBlock extends Block {
 	}
 
 	// Properties
-	private static BlockData blockData;
+	private static BlockData genesisBlockData;
 	private static List<TransactionData> transactionsData;
 	private static List<AssetData> initialAssets;
 
@@ -65,7 +65,7 @@ public class GenesisBlock extends Block {
 	}
 
 	public static GenesisBlock getInstance(Repository repository) throws DataException {
-		return new GenesisBlock(repository, blockData, transactionsData);
+		return new GenesisBlock(repository, genesisBlockData, transactionsData);
 	}
 
 	// Construction from JSON
@@ -73,7 +73,7 @@ public class GenesisBlock extends Block {
 	/** Construct block data from blockchain config */
 	public static void newInstance(GenesisInfo info) {
 		// Should be safe to make this call as BlockChain's instance is set
-		// so we won't be blocked trying to re-enter synchronzied Settings.getInstance()
+		// so we won't be blocked trying to re-enter synchronized Settings.getInstance()
 		BlockChain blockchain = BlockChain.getInstance();
 
 		// Timestamp of zero means "now" but only valid for test nets!
@@ -87,7 +87,7 @@ public class GenesisBlock extends Block {
 			info.timestamp = System.currentTimeMillis();
 		}
 
-		transactionsData = new ArrayList<TransactionData>(Arrays.asList(info.transactions));
+		transactionsData = new ArrayList<>(Arrays.asList(info.transactions));
 
 		// Add default values to transactions
 		transactionsData.stream().forEach(transactionData -> {
@@ -133,7 +133,7 @@ public class GenesisBlock extends Block {
 		int atCount = 0;
 		BigDecimal atFees = BigDecimal.ZERO.setScale(8);
 
-		blockData = new BlockData(info.version, reference, transactionCount, totalFees, transactionsSignature, height, info.timestamp,
+		genesisBlockData = new BlockData(info.version, reference, transactionCount, totalFees, transactionsSignature, height, info.timestamp,
 				generatorPublicKey, generatorSignature, atCount, atFees);
 	}
 
@@ -246,14 +246,14 @@ public class GenesisBlock extends Block {
 
 	@Override
 	public boolean isSignatureValid() {
-		byte[] signature = calcSignature(this.getBlockData());
+		byte[] signature = calcSignature(this.blockData);
 
 		// Validate block signature
-		if (!Arrays.equals(signature, this.getBlockData().getGeneratorSignature()))
+		if (!Arrays.equals(signature, this.blockData.getGeneratorSignature()))
 			return false;
 
 		// Validate transactions signature
-		if (!Arrays.equals(signature, this.getBlockData().getTransactionsSignature()))
+		if (!Arrays.equals(signature, this.blockData.getTransactionsSignature()))
 			return false;
 
 		return true;
@@ -275,10 +275,10 @@ public class GenesisBlock extends Block {
 
 	@Override
 	public void process() throws DataException {
-		LOGGER.info(String.format("Using genesis block timestamp of %d", blockData.getTimestamp()));
+		LOGGER.info(String.format("Using genesis block timestamp of %d", this.blockData.getTimestamp()));
 
 		// If we're a version 1 genesis block, create assets now
-		if (blockData.getVersion() == 1)
+		if (this.blockData.getVersion() == 1)
 			for (AssetData assetData : initialAssets)
 				repository.getAssetRepository().save(assetData);
 

src/main/java/org/qora/brokenmd160.java

@@ -6,7 +6,7 @@ import com.google.common.hash.HashCode;
 @SuppressWarnings("deprecation")
 public class brokenmd160 {
 
-	public static void main(String args[]) {
+	public static void main(String[] args) {
 		if (args.length == 0) {
 			System.err.println("usage: broken-md160 <hex>\noutputs: hex");
 			System.exit(1);

src/main/java/org/qora/controller/ArbitraryDataManager.java

@@ -64,7 +64,7 @@ public class ArbitraryDataManager extends Thread {
 				}
 			}
 		} catch (InterruptedException e) {
-			return;
+			// Fall-through to exit thread...
 		}
 	}
 
@@ -76,7 +76,7 @@ public class ArbitraryDataManager extends Thread {
 	private boolean hasLocalData(final Repository repository, final byte[] signature) {
 		try {
 			TransactionData transactionData = repository.getTransactionRepository().fromSignature(signature);
-			if (transactionData == null || !(transactionData instanceof ArbitraryTransactionData))
+			if (!(transactionData instanceof ArbitraryTransactionData))
 				return true;
 
 			ArbitraryTransaction arbitraryTransaction = new ArbitraryTransaction(repository, transactionData);

src/main/java/org/qora/controller/AutoUpdate.java

@@ -39,7 +39,7 @@ public class AutoUpdate extends Thread {
 	public static final String NEW_JAR_FILENAME = "new-" + JAR_FILENAME;
 
 	private static final Logger LOGGER = LogManager.getLogger(AutoUpdate.class);
-	private static final long CHECK_INTERVAL = 5 * 60 * 1000; // ms
+	private static final long CHECK_INTERVAL = 5 * 60 * 1000L; // ms
 
 	private static final int DEV_GROUP_ID = 1;
 	private static final int UPDATE_SERVICE = 1;
@@ -65,6 +65,7 @@ public class AutoUpdate extends Thread {
 		return instance;
 	}
 
+	@Override
 	public void run() {
 		Thread.currentThread().setName("Auto-update");
 
@@ -94,7 +95,7 @@ public class AutoUpdate extends Thread {
 					continue;
 
 				TransactionData transactionData = repository.getTransactionRepository().fromSignature(signatures.get(0));
-				if (transactionData == null || !(transactionData instanceof ArbitraryTransactionData))
+				if (!(transactionData instanceof ArbitraryTransactionData))
 					continue;
 
 				// Transaction needs to be newer than this build

src/main/java/org/qora/controller/Controller.java

@@ -97,21 +97,21 @@ public class Controller extends Thread {
 	public static final String VERSION_PREFIX = "qora-core-";
 
 	private static final Logger LOGGER = LogManager.getLogger(Controller.class);
-	private static final long MISBEHAVIOUR_COOLOFF = 10 * 60 * 1000; // ms
+	private static final long MISBEHAVIOUR_COOLOFF = 10 * 60 * 1000L; // ms
 	private static final int MAX_BLOCKCHAIN_TIP_AGE = 5; // blocks
 	private static final Object shutdownLock = new Object();
 	private static final String repositoryUrlTemplate = "jdbc:hsqldb:file:%s/blockchain;create=true;hsqldb.full_log_replay=true";
-	private static final long ARBITRARY_REQUEST_TIMEOUT = 5 * 1000; // ms
-	private static final long REPOSITORY_BACKUP_PERIOD = 123 * 60 * 1000; // ms
-	private static final long NTP_PRE_SYNC_CHECK_PERIOD = 5 * 1000; // ms
-	private static final long NTP_POST_SYNC_CHECK_PERIOD = 5 * 60 * 1000; // ms
-	private static final long DELETE_EXPIRED_INTERVAL = 5 * 60 * 1000; // ms
+	private static final long ARBITRARY_REQUEST_TIMEOUT = 5 * 1000L; // ms
+	private static final long REPOSITORY_BACKUP_PERIOD = 123 * 60 * 1000L; // ms
+	private static final long NTP_PRE_SYNC_CHECK_PERIOD = 5 * 1000L; // ms
+	private static final long NTP_POST_SYNC_CHECK_PERIOD = 5 * 60 * 1000L; // ms
+	private static final long DELETE_EXPIRED_INTERVAL = 5 * 60 * 1000L; // ms
 
 	// To do with online accounts list
-	private static final long ONLINE_ACCOUNTS_TASKS_INTERVAL = 10 * 1000; // ms
-	private static final long ONLINE_ACCOUNTS_BROADCAST_INTERVAL = 1 * 60 * 1000; // ms
-	private static final long ONLINE_TIMESTAMP_MODULUS = 5 * 60 * 1000;
-	private static final long LAST_SEEN_EXPIRY_PERIOD = (ONLINE_TIMESTAMP_MODULUS * 2) + (1 * 60 * 1000);
+	private static final long ONLINE_ACCOUNTS_TASKS_INTERVAL = 10 * 1000L; // ms
+	private static final long ONLINE_ACCOUNTS_BROADCAST_INTERVAL = 1 * 60 * 1000L; // ms
+	private static final long ONLINE_TIMESTAMP_MODULUS = 5 * 60 * 1000L;
+	private static final long LAST_SEEN_EXPIRY_PERIOD = (ONLINE_TIMESTAMP_MODULUS * 2) + (1 * 60 * 1000L);
 
 	private static volatile boolean isStopping = false;
 	private static BlockGenerator blockGenerator = null;
@@ -170,18 +170,18 @@ public class Controller extends Thread {
 			throw new RuntimeException("Can't read build.properties resource", e);
 		}
 
-		String buildTimestamp = properties.getProperty("build.timestamp");
-		if (buildTimestamp == null)
+		String buildTimestampProperty = properties.getProperty("build.timestamp");
+		if (buildTimestampProperty == null)
 			throw new RuntimeException("Can't read build.timestamp from build.properties resource");
 
-		this.buildTimestamp = LocalDateTime.parse(buildTimestamp, DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssX")).toEpochSecond(ZoneOffset.UTC);
-		LOGGER.info(String.format("Build timestamp: %s", buildTimestamp));
+		this.buildTimestamp = LocalDateTime.parse(buildTimestampProperty, DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssX")).toEpochSecond(ZoneOffset.UTC);
+		LOGGER.info(String.format("Build timestamp: %s", buildTimestampProperty));
 
-		String buildVersion = properties.getProperty("build.version");
-		if (buildVersion == null)
+		String buildVersionProperty = properties.getProperty("build.version");
+		if (buildVersionProperty == null)
 			throw new RuntimeException("Can't read build.version from build.properties resource");
 
-		this.buildVersion = VERSION_PREFIX + buildVersion;
+		this.buildVersion = VERSION_PREFIX + buildVersionProperty;
 		LOGGER.info(String.format("Build version: %s", this.buildVersion));
 	}
 
@@ -231,7 +231,7 @@ public class Controller extends Thread {
 
 	// Entry point
 
-	public static void main(String args[]) {
+	public static void main(String[] args) {
 		LOGGER.info("Starting up...");
 
 		// Potential GUI startup with splash screen, etc.
@@ -282,7 +282,7 @@ public class Controller extends Thread {
 		LOGGER.info("Starting controller");
 		Controller.getInstance().start();
 
-		LOGGER.info("Starting networking on port " + Settings.getInstance().getListenPort());
+		LOGGER.info(String.format("Starting networking on port %d", Settings.getInstance().getListenPort()));
 		try {
 			Network network = Network.getInstance();
 			network.start();
@@ -312,7 +312,7 @@ public class Controller extends Thread {
 		LOGGER.info("Starting auto-update");
 		AutoUpdate.getInstance().start();
 
-		LOGGER.info("Starting API on port " + Settings.getInstance().getApiPort());
+		LOGGER.info(String.format("Starting API on port %d", Settings.getInstance().getApiPort()));
 		try {
 			ApiService apiService = ApiService.getInstance();
 			apiService.start();
@@ -321,7 +321,7 @@ public class Controller extends Thread {
 			System.exit(1);
 		}
 
-		LOGGER.info("Starting node management UI on port " + Settings.getInstance().getUiPort());
+		LOGGER.info(String.format("Starting node management UI on port %d", Settings.getInstance().getUiPort()));
 		try {
 			UiService uiService = UiService.getInstance();
 			uiService.start();
@@ -335,7 +335,7 @@ public class Controller extends Thread {
 	}
 
 	/** Called by AdvancedInstaller's launch EXE in single-instance mode, when an instance is already running. */
-	public static void secondaryMain(String args[]) {
+	public static void secondaryMain(String[] args) {
 		// Return as we don't want to run more than one instance
 	}
 
@@ -670,7 +670,7 @@ public class Controller extends Thread {
 		network.broadcast(peer -> network.buildHeightMessage(peer, latestBlockData));
 
 		// Send (if outbound) / Request unconfirmed transaction signatures
-		network.broadcast(peer -> network.buildGetUnconfirmedTransactionsMessage(peer));
+		network.broadcast(network::buildGetUnconfirmedTransactionsMessage);
 	}
 
 	public void onGenerationPossibleChange(boolean isGenerationPossible) {
@@ -1002,7 +1002,7 @@ public class Controller extends Thread {
 						// Fetch actual transaction data from peer
 						Message getTransactionMessage = new GetTransactionMessage(signature);
 						Message responseMessage = peer.getResponse(getTransactionMessage);
-						if (responseMessage == null || !(responseMessage instanceof TransactionMessage)) {
+						if (!(responseMessage instanceof TransactionMessage)) {
 							// Maybe peer no longer has this transaction
 							LOGGER.trace(() -> String.format("Peer %s didn't send transaction %s", peer, Base58.encode(signature)));
 							continue;
@@ -1158,7 +1158,7 @@ public class Controller extends Thread {
 				// Check transaction exists and payload hash is correct
 				try (final Repository repository = RepositoryManager.getRepository()) {
 					TransactionData transactionData = repository.getTransactionRepository().fromSignature(signature);
-					if (transactionData == null || !(transactionData instanceof ArbitraryTransactionData))
+					if (!(transactionData instanceof ArbitraryTransactionData))
 						break;
 
 					ArbitraryTransactionData arbitraryTransactionData = (ArbitraryTransactionData) transactionData;
@@ -1231,10 +1231,10 @@ public class Controller extends Thread {
 			case ONLINE_ACCOUNTS: {
 				OnlineAccountsMessage onlineAccountsMessage = (OnlineAccountsMessage) message;
 
-				List<OnlineAccountData> onlineAccounts = onlineAccountsMessage.getOnlineAccounts();
-				LOGGER.trace(() -> String.format("Received %d online accounts from %s", onlineAccounts.size(), peer));
+				List<OnlineAccountData> peersOnlineAccounts = onlineAccountsMessage.getOnlineAccounts();
+				LOGGER.trace(() -> String.format("Received %d online accounts from %s", peersOnlineAccounts.size(), peer));
 
-				for (OnlineAccountData onlineAccountData : onlineAccounts)
+				for (OnlineAccountData onlineAccountData : peersOnlineAccounts)
 					this.verifyAndAddAccount(onlineAccountData);
 
 				break;
@@ -1309,7 +1309,7 @@ public class Controller extends Thread {
 			synchronized (this.onlineAccounts) {
 				message = new GetOnlineAccountsMessage(this.onlineAccounts);
 			}
-			Network.getInstance().broadcast((peer) -> message);
+			Network.getInstance().broadcast(peer -> message);
 		}
 
 		// Refresh our online accounts signatures?
@@ -1341,7 +1341,7 @@ public class Controller extends Thread {
 					iterator.remove();
 			}
 		} catch (DataException e) {
-			LOGGER.warn("Repository issue trying to fetch forging accounts: " + e.getMessage());
+			LOGGER.warn(String.format("Repository issue trying to fetch forging accounts: %s", e.getMessage()));
 			return;
 		}
 
@@ -1389,7 +1389,7 @@ public class Controller extends Thread {
 			return;
 
 		Message message = new OnlineAccountsMessage(ourOnlineAccounts);
-		Network.getInstance().broadcast((peer) -> message);
+		Network.getInstance().broadcast(peer -> message);
 
 		LOGGER.trace(()-> String.format("Broadcasted %d online account%s with timestamp %d", ourOnlineAccounts.size(), (ourOnlineAccounts.size() != 1 ? "s" : ""), onlineAccountsTimestamp));
 	}

src/main/java/org/qora/controller/Synchronizer.java

@@ -214,7 +214,7 @@ public class Synchronizer {
 							--ourHeight;
 						}
 
-						LOGGER.debug(String.format("Orphaned blocks back to height %d, sig %.8s - fetching blocks from peer", commonBlockHeight, commonBlockSig58, peer));
+						LOGGER.debug(String.format("Orphaned blocks back to height %d, sig %.8s - fetching blocks from peer %s", commonBlockHeight, commonBlockSig58, peer));
 					} else {
 						LOGGER.debug(String.format("Fetching new blocks from peer %s", peer));
 					}
@@ -224,7 +224,7 @@ public class Synchronizer {
 					int maxBatchHeight = commonBlockHeight + SYNC_BATCH_SIZE;
 
 					// Convert any block summaries from above into signatures to request from peer
-					List<byte[]> peerBlockSignatures = peerBlockSummaries.stream().map(blockSummaryData -> blockSummaryData.getSignature()).collect(Collectors.toList());
+					List<byte[]> peerBlockSignatures = peerBlockSummaries.stream().map(BlockSummaryData::getSignature).collect(Collectors.toList());
 
 					while (ourHeight < peerHeight && ourHeight < maxBatchHeight) {
 						// Do we need more signatures?

src/main/java/org/qora/crosschain/BTC.java

@@ -196,12 +196,9 @@ public class BTC {
 		peerGroup.start();
 	}
 
-	public static BTC getInstance() {
+	public static synchronized BTC getInstance() {
 		if (instance == null)
-			synchronized (instanceLock) {
-				if (instance == null)
-					instance = new BTC();
-			}
+			instance = new BTC();
 
 		return instance;
 	}

src/main/java/org/qora/crypto/BrokenMD160.java

@@ -6,8 +6,8 @@ package org.qora.crypto;
  * <b>DO NOT USE in future code</b> as this implementation is BROKEN and returns incorrect digests for some inputs.
  * <p>
  * It is only "grand-fathered" here to produce correct QORA addresses.
+ * @deprecated
  */
-
 @Deprecated
 public class BrokenMD160 {
 

src/main/java/org/qora/data/voting/PollData.java

@@ -2,8 +2,6 @@ package org.qora.data.voting;
 
 import java.util.List;
 
-import org.qora.data.voting.PollOptionData;
-
 public class PollData {
 
 	// Properties

src/main/java/org/qora/globalization/BIP39WordList.java

@@ -33,13 +33,13 @@ public enum BIP39WordList {
 
 			try (InputStream inputStream = loader.getResourceAsStream("BIP39/wordlist_" + lang + ".txt")) {
 				if (inputStream == null) {
-					LOGGER.warn("Can't locate '" + lang + "' BIP39 wordlist");
+					LOGGER.warn(String.format("Can't locate '%s' BIP39 wordlist", lang));
 					return null;
 				}
 
 				wordList = new BufferedReader(new InputStreamReader(inputStream)).lines().collect(Collectors.toList());
 			} catch (IOException e) {
-				LOGGER.warn("Error reading '" + lang + "' BIP39 wordlist", e);
+				LOGGER.warn(String.format("Error reading '%s' BIP39 wordlist", lang), e);
 				return null;
 			}
 

src/main/java/org/qora/group/Group.java

@@ -46,7 +46,7 @@ public class Group {
 		public final int value;
 		public final boolean isPercentage;
 
-		private final static Map<Integer, ApprovalThreshold> map = stream(ApprovalThreshold.values())
+		private static final Map<Integer, ApprovalThreshold> map = stream(ApprovalThreshold.values())
 				.collect(toMap(threshold -> threshold.value, threshold -> threshold));
 
 		ApprovalThreshold(int value, boolean isPercentage) {

src/main/java/org/qora/gui/SplashFrame.java

@@ -41,7 +41,7 @@ public class SplashFrame {
 	private SplashFrame() {
 		this.splashDialog = new JDialog();
 
-		List<Image> icons = new ArrayList<Image>();
+		List<Image> icons = new ArrayList<>();
 		icons.add(Gui.loadImage("icons/icon16.png"));
 		icons.add(Gui.loadImage("icons/icon32.png"));
 		icons.add(Gui.loadImage("icons/icon64.png"));

src/main/java/org/qora/gui/SysTray.java

@@ -4,8 +4,6 @@ import java.awt.AWTError;
 import java.awt.AWTException;
 import java.awt.SystemTray;
 import java.awt.TrayIcon;
-import java.awt.event.ActionEvent;
-import java.awt.event.ActionListener;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
 import java.awt.event.WindowEvent;
@@ -37,7 +35,7 @@ import org.qora.utils.URLViewer;
 
 public class SysTray {
 
-	protected static final Logger LOGGER = LogManager.getLogger(SplashFrame.class);
+	protected static final Logger LOGGER = LogManager.getLogger(SysTray.class);
 	private static final String NTP_SCRIPT = "ntpcfg.bat";
 
 	private static SysTray instance;
@@ -147,31 +145,25 @@ public class SysTray {
 		});
 
 		JMenuItem openUi = new JMenuItem(Translator.INSTANCE.translate("SysTray", "OPEN_NODE_UI"));
-		openUi.addActionListener(new ActionListener() {
-			@Override
-			public void actionPerformed(ActionEvent e) {
-				destroyHiddenDialog();
+		openUi.addActionListener(actionEvent -> {
+			destroyHiddenDialog();
 
-				try {
-					URLViewer.openWebpage(new URL("http://localhost:" + Settings.getInstance().getUiPort()));
-				} catch (Exception e1) {
-					LOGGER.error("Unable to open node UI in browser");
-				}
+			try {
+				URLViewer.openWebpage(new URL("http://localhost:" + Settings.getInstance().getUiPort()));
+			} catch (Exception e) {
+				LOGGER.error("Unable to open node UI in browser");
 			}
 		});
 		menu.add(openUi);
 
 		JMenuItem openTimeCheck = new JMenuItem(Translator.INSTANCE.translate("SysTray", "CHECK_TIME_ACCURACY"));
-		openTimeCheck.addActionListener(new ActionListener() {
-			@Override
-			public void actionPerformed(ActionEvent e) {
-				destroyHiddenDialog();
+		openTimeCheck.addActionListener(actionEvent -> {
+			destroyHiddenDialog();
 
-				try {
-					URLViewer.openWebpage(new URL("https://time.is"));
-				} catch (Exception e1) {
-					LOGGER.error("Unable to open time-check website in browser");
-				}
+			try {
+				URLViewer.openWebpage(new URL("https://time.is"));
+			} catch (Exception e) {
+				LOGGER.error("Unable to open time-check website in browser");
 			}
 		});
 		menu.add(openTimeCheck);
@@ -179,25 +171,19 @@ public class SysTray {
 		// Only for Windows users
 		if (System.getProperty("os.name").toLowerCase().contains("win")) {
 			JMenuItem syncTime = new JMenuItem(Translator.INSTANCE.translate("SysTray", "SYNCHRONIZE_CLOCK"));
-			syncTime.addActionListener(new ActionListener() {
-				@Override
-				public void actionPerformed(ActionEvent e) {
-					destroyHiddenDialog();
+			syncTime.addActionListener(actionEvent -> {
+				destroyHiddenDialog();
 
-					new SynchronizeWorker().execute();
-				}
+				new SynchronizeWorker().execute();
 			});
 			menu.add(syncTime);
 		}
 
 		JMenuItem exit = new JMenuItem(Translator.INSTANCE.translate("SysTray", "EXIT"));
-		exit.addActionListener(new ActionListener() {
-			@Override
-			public void actionPerformed(ActionEvent e) {
-				destroyHiddenDialog();
+		exit.addActionListener(actionEvent -> {
+			destroyHiddenDialog();
 
-				new ClosingWorker().execute();
-			}
+			new ClosingWorker().execute();
 		});
 		menu.add(exit);
 

src/main/java/org/qora/mintsim.java

@@ -44,7 +44,7 @@ public class mintsim {
 		}
 	}
 
-	public static void main(String args[]) {
+	public static void main(String[] args) {
 		if (args.length < 2 || (args.length % 2) != 0) {
 			System.err.println("usage: mintsim <tier1-min-blocks> <number-tier1-accounts> [<tier2-min-blocks> <max-tier2-per-tier1> [...]]");
 			System.exit(1);
@@ -53,8 +53,8 @@ public class mintsim {
 		try {
 			int argIndex = 0;
 			do {
-				int minBlocks = Integer.valueOf(args[argIndex++]);
-				int maxAccounts = Integer.valueOf(args[argIndex++]);
+				int minBlocks = Integer.parseInt(args[argIndex++]);
+				int maxAccounts = Integer.parseInt(args[argIndex++]);
 
 				tiers.add(new TierInfo(maxAccounts, minBlocks));
 			} while (argIndex < args.length);

src/main/java/org/qora/network/Handshake.java

@@ -201,7 +201,7 @@ public enum Handshake {
 	private static final Logger LOGGER = LogManager.getLogger(Handshake.class);
 
 	/** Maximum allowed difference between peer's reported timestamp and when they connected, in milliseconds. */
-	private static final long MAX_TIMESTAMP_DELTA = 30 * 1000; // ms
+	private static final long MAX_TIMESTAMP_DELTA = 30 * 1000L; // ms
 
 	public final MessageType expectedMessageType;
 

src/main/java/org/qora/network/Network.java

@@ -59,22 +59,22 @@ import org.qora.utils.ExecuteProduceConsume;
 import org.qora.utils.NTP;
 
 // For managing peers
-public class Network extends Thread {
+public class Network {
 
 	private static final Logger LOGGER = LogManager.getLogger(Network.class);
 	private static Network instance;
 
 	private static final int LISTEN_BACKLOG = 10;
 	/** How long before retrying after a connection failure, in milliseconds. */
-	private static final int CONNECT_FAILURE_BACKOFF = 5 * 60 * 1000; // ms
+	private static final long CONNECT_FAILURE_BACKOFF = 5 * 60 * 1000L; // ms
 	/** How long between informational broadcasts to all connected peers, in milliseconds. */
-	private static final int BROADCAST_INTERVAL = 60 * 1000; // ms
+	private static final long BROADCAST_INTERVAL = 60 * 1000L; // ms
 	/** Maximum time since last successful connection for peer info to be propagated, in milliseconds. */
-	private static final long RECENT_CONNECTION_THRESHOLD = 24 * 60 * 60 * 1000; // ms
+	private static final long RECENT_CONNECTION_THRESHOLD = 24 * 60 * 60 * 1000L; // ms
 	/** Maximum time since last connection attempt before a peer is potentially considered "old", in milliseconds. */
-	private static final long OLD_PEER_ATTEMPTED_PERIOD = 24 * 60 * 60 * 1000; // ms
+	private static final long OLD_PEER_ATTEMPTED_PERIOD = 24 * 60 * 60 * 1000L; // ms
 	/** Maximum time since last successful connection before a peer is potentially considered "old", in milliseconds. */
-	private static final long OLD_PEER_CONNECTION_PERIOD = 7 * 24 * 60 * 60 * 1000; // ms
+	private static final long OLD_PEER_CONNECTION_PERIOD = 7 * 24 * 60 * 60 * 1000L; // ms
 	/** Maximum time allowed for handshake to complete, in milliseconds. */
 	private static final long HANDSHAKE_TIMEOUT = 60 * 1000; // ms
 
@@ -135,7 +135,7 @@ public class Network extends Thread {
 			serverChannel.bind(endpoint, LISTEN_BACKLOG);
 			serverChannel.register(channelSelector, SelectionKey.OP_ACCEPT);
 		} catch (UnknownHostException e) {
-			LOGGER.error("Can't bind listen socket to address " + Settings.getInstance().getBindAddress());
+			LOGGER.error(String.format("Can't bind listen socket to address %s", Settings.getInstance().getBindAddress()));
 			throw new RuntimeException("Can't bind listen socket to address");
 		} catch (IOException e) {
 			LOGGER.error("Can't create listen socket");
@@ -167,7 +167,9 @@ public class Network extends Thread {
 				10L, TimeUnit.SECONDS,
 				new SynchronousQueue<Runnable>());
 		networkEPC = new NetworkProcessor(networkExecutor);
+	}
 
+	public void start() {
 		// Start up first networking thread
 		networkEPC.start();
 	}
@@ -244,14 +246,9 @@ public class Network extends Thread {
 
 	/** Returns list of peers we connected to that have completed handshaking. */
 	public List<Peer> getOutboundHandshakedPeers() {
-		List<Peer> peers = new ArrayList<>();
-
 		synchronized (this.connectedPeers) {
-			peers = this.connectedPeers.stream().filter(peer -> peer.isOutbound() && peer.getHandshakeStatus() == Handshake.COMPLETED)
-					.collect(Collectors.toList());
+			return this.connectedPeers.stream().filter(peer -> peer.isOutbound() && peer.getHandshakeStatus() == Handshake.COMPLETED).collect(Collectors.toList());
 		}
-
-		return peers;
 	}
 
 	/** Returns Peer with inbound connection and matching ID, or null if none found. */
@@ -359,9 +356,7 @@ public class Network extends Thread {
 
 					LOGGER.trace(() -> String.format("Network thread %s encountered I/O error: %s", Thread.currentThread().getId(), e.getMessage()), e);
 					peer.disconnect("I/O error");
-					return;
 				}
-
 			}
 		}
 
@@ -664,7 +659,7 @@ public class Network extends Thread {
 		if (socketChannel == null)
 			return;
 
-		if (this.isInterrupted())
+		if (Thread.currentThread().isInterrupted())
 			return;
 
 		synchronized (this.connectedPeers) {
@@ -839,7 +834,7 @@ public class Network extends Thread {
 				// If inbound peer, use listen port and socket address to recreate first entry
 				if (!peer.isOutbound()) {
 					PeerAddress sendingPeerAddress = PeerAddress.fromString(peer.getPeerData().getAddress().getHost() + ":" + peerPort);
-					LOGGER.trace("PEERS_V2 sending peer's listen address: " + sendingPeerAddress.toString());
+					LOGGER.trace(() -> String.format("PEERS_V2 sending peer's listen address: %s", sendingPeerAddress.toString()));
 					peerV2Addresses.add(0, sendingPeerAddress);
 				}
 
@@ -1100,10 +1095,7 @@ public class Network extends Thread {
 				List<PeerData> knownPeers = repository.getNetworkRepository().getAllPeers();
 
 				// Filter out duplicates
-				Predicate<PeerAddress> isKnownAddress = peerAddress -> {
-					return knownPeers.stream().anyMatch(knownPeerData -> knownPeerData.getAddress().equals(peerAddress));
-				};
-
+				Predicate<PeerAddress> isKnownAddress = peerAddress -> knownPeers.stream().anyMatch(knownPeerData -> knownPeerData.getAddress().equals(peerAddress));
 				peerAddresses.removeIf(isKnownAddress);
 
 				repository.discardChanges();
@@ -1126,6 +1118,8 @@ public class Network extends Thread {
 
 	public void broadcast(Function<Peer, Message> peerMessageBuilder) {
 		class Broadcaster implements Runnable {
+			private final Random random = new Random();
+
 			private List<Peer> targetPeers;
 			private Function<Peer, Message> peerMessageBuilder;
 
@@ -1138,12 +1132,10 @@ public class Network extends Thread {
 			public void run() {
 				Thread.currentThread().setName("Network Broadcast");
 
-				Random random = new Random();
-
 				for (Peer peer : targetPeers) {
 					// Very short sleep to reduce strain, improve multi-threading and catch interrupts
 					try {
-						Thread.sleep(random.nextInt(20) + 20);
+						Thread.sleep(random.nextInt(20) + 20L);
 					} catch (InterruptedException e) {
 						break;
 					}

src/main/java/org/qora/network/Peer.java

@@ -256,7 +256,7 @@ public class Peer {
 		this.socketChannel.configureBlocking(false);
 		this.byteBuffer = ByteBuffer.allocate(Network.getInstance().getMaxMessageSize());
 		this.replyQueues = Collections.synchronizedMap(new HashMap<Integer, BlockingQueue<Message>>());
-		this.pendingMessages = new LinkedBlockingQueue<Message>();
+		this.pendingMessages = new LinkedBlockingQueue<>();
 	}
 
 	public SocketChannel connect() {
@@ -394,7 +394,7 @@ public class Peer {
 					if (bytesWritten == 0)
 						// Underlying socket's internal buffer probably full,
 						// so wait a short while for bytes to actually be transmitted over the wire
-						Thread.sleep(1L);
+						this.socketChannel.wait(1L);
 				}
 			}
 		} catch (MessageException e) {
@@ -424,7 +424,7 @@ public class Peer {
 	 * @throws InterruptedException
 	 */
 	public Message getResponse(Message message) throws InterruptedException {
-		BlockingQueue<Message> blockingQueue = new ArrayBlockingQueue<Message>(1);
+		BlockingQueue<Message> blockingQueue = new ArrayBlockingQueue<>(1);
 
 		// Assign random ID to this message
 		int id;
@@ -443,8 +443,7 @@ public class Peer {
 		}
 
 		try {
-			Message response = blockingQueue.poll(RESPONSE_TIMEOUT, TimeUnit.MILLISECONDS);
-			return response;
+			return blockingQueue.poll(RESPONSE_TIMEOUT, TimeUnit.MILLISECONDS);
 		} finally {
 			this.replyQueues.remove(id);
 		}

src/main/java/org/qora/network/message/Message.java

@@ -73,7 +73,7 @@ public abstract class Message {
 		ONLINE_ACCOUNTS(26);
 
 		public final int value;
-		public final Method fromByteBuffer;
+		public final Method fromByteBufferMethod;
 
 		private static final Map<Integer, MessageType> map = stream(MessageType.values())
 				.collect(toMap(messageType -> messageType.value, messageType -> messageType));
@@ -88,16 +88,16 @@ public abstract class Message {
 
 			String className = String.join("", classNameParts);
 
-			Method fromByteBuffer;
+			Method method;
 			try {
 				Class<?> subclass = Class.forName(String.join("", Message.class.getPackage().getName(), ".", className, "Message"));
 
-				fromByteBuffer = subclass.getDeclaredMethod("fromByteBuffer", int.class, ByteBuffer.class);
+				method = subclass.getDeclaredMethod("fromByteBuffer", int.class, ByteBuffer.class);
 			} catch (ClassNotFoundException | NoSuchMethodException | SecurityException e) {
-				fromByteBuffer = null;
+				method = null;
 			}
 
-			this.fromByteBuffer = fromByteBuffer;
+			this.fromByteBufferMethod = method;
 		}
 
 		public static MessageType valueOf(int value) {
@@ -105,11 +105,11 @@ public abstract class Message {
 		}
 
 		public Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
-			if (this.fromByteBuffer == null)
+			if (this.fromByteBufferMethod == null)
 				throw new MessageException("Unsupported message type [" + value + "] during conversion from bytes");
 
 			try {
-				return (Message) this.fromByteBuffer.invoke(null, id, byteBuffer);
+				return (Message) this.fromByteBufferMethod.invoke(null, id, byteBuffer);
 			} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
 				if (e.getCause() instanceof BufferUnderflowException)
 					throw new MessageException("Byte data too short for " + name() + " message");

src/main/java/org/qora/network/message/PeersV2Message.java

@@ -4,6 +4,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -42,7 +43,7 @@ public class PeersV2Message extends Message {
 
 			byte[] addressBytes = new byte[addressSize & 0xff];
 			byteBuffer.get(addressBytes);
-			String addressString = new String(addressBytes, "UTF-8");
+			String addressString = new String(addressBytes, StandardCharsets.UTF_8);
 
 			try {
 				PeerAddress peerAddress = PeerAddress.fromString(addressString);
@@ -63,10 +64,10 @@ public class PeersV2Message extends Message {
 			List<byte[]> addresses = new ArrayList<>();
 
 			// First entry represents sending node but contains only port number with empty address.
-			addresses.add(new String("0.0.0.0:" + Settings.getInstance().getListenPort()).getBytes("UTF-8"));
+			addresses.add(("0.0.0.0:" + Settings.getInstance().getListenPort()).getBytes(StandardCharsets.UTF_8));
 
 			for (PeerAddress peerAddress : this.peerAddresses)
-				addresses.add(peerAddress.toString().getBytes("UTF-8"));
+				addresses.add(peerAddress.toString().getBytes(StandardCharsets.UTF_8));
 
 			// We can't send addresses that are longer than 255 bytes as length itself is encoded in one byte.
 			addresses.removeIf(addressString -> addressString.length > 255);

src/main/java/org/qora/network/message/VersionMessage.java

@@ -4,6 +4,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 
 import org.qora.utils.Serialization;
 
@@ -44,7 +45,7 @@ public class VersionMessage extends Message {
 		byte[] versionBytes = new byte[versionStringLength];
 		bytes.get(versionBytes);
 
-		String versionString = new String(versionBytes, "UTF-8");
+		String versionString = new String(versionBytes, StandardCharsets.UTF_8);
 
 		return new VersionMessage(id, buildTimestamp, versionString);
 	}

src/main/java/org/qora/payment/Payment.java

@@ -45,7 +45,7 @@ public class Payment {
 			return ValidationResult.NEGATIVE_FEE;
 
 		// Total up payment amounts by assetId
-		Map<Long, BigDecimal> amountsByAssetId = new HashMap<Long, BigDecimal>();
+		Map<Long, BigDecimal> amountsByAssetId = new HashMap<>();
 		// Add transaction fee to start with
 		amountsByAssetId.put(Asset.QORT, fee);
 

src/main/java/org/qora/repository/hsqldb/HSQLDBATRepository.java

@@ -188,7 +188,7 @@ public class HSQLDBATRepository implements ATRepository {
 
 	@Override
 	public List<ATStateData> getBlockATStatesAtHeight(int height) throws DataException {
-		List<ATStateData> atStates = new ArrayList<ATStateData>();
+		List<ATStateData> atStates = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute("SELECT AT_address, state_hash, fees FROM ATStates WHERE height = ? ORDER BY creation ASC",
 				height)) {

src/main/java/org/qora/repository/hsqldb/HSQLDBAccountRepository.java

@@ -321,7 +321,7 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 
 		// For no-address queries, or unless specifically requested, only return accounts with non-zero balance
-		if (addresses.isEmpty() || (excludeZero != null && excludeZero == true)) {
+		if (addresses.isEmpty() || (excludeZero != null && excludeZero)) {
 			sql.append(assetIds.isEmpty() ? " WHERE " : " AND ");
 			sql.append("balance != 0 ");
 		}

src/main/java/org/qora/repository/hsqldb/HSQLDBAssetRepository.java

@@ -104,7 +104,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<AssetData> assets = new ArrayList<AssetData>();
+		List<AssetData> assets = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString())) {
 			if (resultSet == null)
@@ -228,7 +228,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 	@Override
 	public List<OrderData> getOpenOrders(long haveAssetId, long wantAssetId, Integer limit, Integer offset,
 			Boolean reverse) throws DataException {
-		List<OrderData> orders = new ArrayList<OrderData>();
+		List<OrderData> orders = new ArrayList<>();
 
 		// Cache have & want asset names for later use, which also saves a table join
 		AssetData haveAssetData = this.fromAssetId(haveAssetId);
@@ -305,7 +305,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 
 		sql.append(", ordered");
 
-		List<OrderData> orders = new ArrayList<OrderData>();
+		List<OrderData> orders = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), bindParams.toArray())) {
 			if (resultSet == null)
@@ -336,7 +336,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 	@Override
 	public List<OrderData> getAggregatedOpenOrders(long haveAssetId, long wantAssetId, Integer limit, Integer offset,
 			Boolean reverse) throws DataException {
-		List<OrderData> orders = new ArrayList<OrderData>();
+		List<OrderData> orders = new ArrayList<>();
 
 		// Cache have & want asset names for later use, which also saves a table join
 		AssetData haveAssetData = this.fromAssetId(haveAssetId);
@@ -404,7 +404,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<OrderData> orders = new ArrayList<OrderData>();
+		List<OrderData> orders = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), publicKey)) {
 			if (resultSet == null)
@@ -437,7 +437,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 	@Override
 	public List<OrderData> getAccountsOrders(byte[] publicKey, long haveAssetId, long wantAssetId, Boolean optIsClosed,
 			Boolean optIsFulfilled, Integer limit, Integer offset, Boolean reverse) throws DataException {
-		List<OrderData> orders = new ArrayList<OrderData>();
+		List<OrderData> orders = new ArrayList<>();
 
 		// Cache have & want asset names for later use, which also saves a table join
 		AssetData haveAssetData = this.fromAssetId(haveAssetId);
@@ -524,7 +524,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 	@Override
 	public List<TradeData> getTrades(long haveAssetId, long wantAssetId, Integer limit, Integer offset, Boolean reverse)
 			throws DataException {
-		List<TradeData> trades = new ArrayList<TradeData>();
+		List<TradeData> trades = new ArrayList<>();
 
 		// Cache have & want asset names for later use, which also saves a table join
 		AssetData haveAssetData = this.fromAssetId(haveAssetId);
@@ -677,7 +677,7 @@ public class HSQLDBAssetRepository implements AssetRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<TradeData> trades = new ArrayList<TradeData>();
+		List<TradeData> trades = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), orderId)) {
 			if (resultSet == null)

src/main/java/org/qora/repository/hsqldb/HSQLDBBlockRepository.java

@@ -153,7 +153,7 @@ public class HSQLDBBlockRepository implements BlockRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), signature)) {
 			if (resultSet == null)

src/main/java/org/qora/repository/hsqldb/HSQLDBDatabaseUpdates.java

@@ -29,8 +29,10 @@ public class HSQLDBDatabaseUpdates {
 	 * @throws SQLException
 	 */
 	private static void incrementDatabaseVersion(Connection connection) throws SQLException {
-		connection.createStatement().execute("UPDATE DatabaseInfo SET version = version + 1");
-		connection.commit();
+		try (Statement stmt = connection.createStatement()) {
+			stmt.execute("UPDATE DatabaseInfo SET version = version + 1");
+			connection.commit();
+		}
 	}
 
 	/**

src/main/java/org/qora/repository/hsqldb/HSQLDBGroupRepository.java

@@ -308,9 +308,7 @@ public class HSQLDBGroupRepository implements GroupRepository {
 			if (resultSet == null)
 				return null;
 
-			String owner = resultSet.getString(1);
-
-			return owner;
+			return resultSet.getString(1);
 		} catch (SQLException e) {
 			throw new DataException("Unable to fetch group owner from repository", e);
 		}

src/main/java/org/qora/repository/hsqldb/HSQLDBRepository.java

@@ -63,7 +63,7 @@ public class HSQLDBRepository implements Repository {
 
 		this.slowQueryThreshold = Settings.getInstance().getSlowQueryThreshold();
 		if (this.slowQueryThreshold != null)
-			this.sqlStatements = new ArrayList<String>();
+			this.sqlStatements = new ArrayList<>();
 
 		// Find out our session ID
 		try (Statement stmt = this.connection.createStatement()) {
@@ -237,13 +237,13 @@ public class HSQLDBRepository implements Repository {
 
 	@Override
 	public void backup(boolean quick) throws DataException {
-		// First perform a CHECKPOINT
-		try {
-			if (!quick)
-				this.connection.createStatement().execute("CHECKPOINT DEFRAG");
-		} catch (SQLException e) {
-			throw new DataException("Unable to prepare repository for backup");
-		}
+		if (!quick)
+			// First perform a CHECKPOINT
+			try (Statement stmt = this.connection.createStatement()) {
+				stmt.execute("CHECKPOINT DEFRAG");
+			} catch (SQLException e) {
+				throw new DataException("Unable to prepare repository for backup");
+			}
 
 		// Clean out any previous backup
 		try {
@@ -272,8 +272,8 @@ public class HSQLDBRepository implements Repository {
 		}
 
 		// Actually create backup
-		try {
-			this.connection.createStatement().execute("BACKUP DATABASE TO 'backup/' NOT BLOCKING AS FILES");
+		try (Statement stmt = this.connection.createStatement()) {
+			stmt.execute("BACKUP DATABASE TO 'backup/' NOT BLOCKING AS FILES");
 		} catch (SQLException e) {
 			throw new DataException("Unable to backup repository");
 		}
@@ -287,8 +287,7 @@ public class HSQLDBRepository implements Repository {
 		if (!matcher.find())
 			return null;
 
-		String pathname = matcher.group(1);
-		return pathname;
+		return matcher.group(1);
 	}
 
 	private static String buildBackupUrl(String dbPathname) {
@@ -298,8 +297,7 @@ public class HSQLDBRepository implements Repository {
 
 		// Try to open backup. We need to remove "create=true" and insert "backup" dir before final filename.
 		String backupUrlTemplate = "jdbc:hsqldb:file:%s/backup/%s;create=false;hsqldb.full_log_replay=true";
-		String backupUrl = String.format(backupUrlTemplate, oldRepoDirPath.toString(), oldRepoFilePath.toString());
-		return backupUrl;
+		return String.format(backupUrlTemplate, oldRepoDirPath.toString(), oldRepoFilePath.toString());
 	}
 
 	/* package */ static void attemptRecovery(String connectionUrl) throws DataException {
@@ -321,11 +319,11 @@ public class HSQLDBRepository implements Repository {
 					.filter(file -> file.getPath().startsWith(dbPathname))
 					.forEach(File::delete);
 
-			try {
+			try (Statement stmt = connection.createStatement()) {
 				// Now "backup" the backup back to original repository location (the parent)
 				// NOTE: trailing / is OK because HSQLDB checks for both / and O/S-specific separator
 				// textdb.allow_full_path connection property is required to be able to use '..'
-				connection.createStatement().execute("BACKUP DATABASE TO '../' BLOCKING AS FILES");
+				stmt.execute("BACKUP DATABASE TO '../' BLOCKING AS FILES");
 			} catch (SQLException e) {
 				// We really failed
 				throw new DataException("Failed to recover repository to original location");
@@ -357,9 +355,7 @@ public class HSQLDBRepository implements Repository {
 		if (this.sqlStatements != null)
 			this.sqlStatements.add(sql);
 
-		PreparedStatement preparedStatement = this.connection.prepareStatement(sql);
-
-		return preparedStatement;
+		return this.connection.prepareStatement(sql);
 	}
 
 	/**
@@ -594,7 +590,7 @@ public class HSQLDBRepository implements Repository {
 				return e;
 
 			do {
-				long sessionId = resultSet.getLong(1);
+				long systemSessionId = resultSet.getLong(1);
 				boolean inTransaction = resultSet.getBoolean(2);
 				long transactionSize = resultSet.getLong(3);
 				String waitingForThis = resultSet.getString(4);
@@ -602,7 +598,7 @@ public class HSQLDBRepository implements Repository {
 				String currentStatement = resultSet.getString(6);
 
 				LOGGER.error(String.format("Session %d, %s transaction (size %d), waiting for this '%s', this waiting for '%s', current statement: %s",
-						sessionId, (inTransaction ? "in" : "not in"), transactionSize, waitingForThis, thisWaitingFor, currentStatement));
+						systemSessionId, (inTransaction ? "in" : "not in"), transactionSize, waitingForThis, thisWaitingFor, currentStatement));
 			} while (resultSet.next());
 		} catch (SQLException de) {
 			// Throw original exception instead
@@ -619,8 +615,10 @@ public class HSQLDBRepository implements Repository {
 				throw new DataException("Unable to check repository status after " + context);
 
 			try (ResultSet resultSet = stmt.getResultSet()) {
-				if (resultSet == null || !resultSet.next())
-					LOGGER.warn("Unable to check repository status after " + context);
+				if (resultSet == null || !resultSet.next()) {
+					LOGGER.warn(String.format("Unable to check repository status after %s", context));
+					return;
+				}
 
 				boolean inTransaction = resultSet.getBoolean(1);
 				int transactionCount = resultSet.getInt(2);

src/main/java/org/qora/repository/hsqldb/HSQLDBRepositoryFactory.java

@@ -3,6 +3,7 @@ package org.qora.repository.hsqldb;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.Properties;
 
 import org.apache.logging.log4j.LogManager;
@@ -31,9 +32,10 @@ public class HSQLDBRepositoryFactory implements RepositoryFactory {
 
 		// Check no-one else is accessing database
 		try (Connection connection = DriverManager.getConnection(this.connectionUrl)) {
+			// We only need to check we can obtain connection. It will be auto-closed.
 		} catch (SQLException e) {
 			Throwable cause = e.getCause();
-			if (cause == null || !(cause instanceof HsqlException))
+			if (!(cause instanceof HsqlException))
 				throw new DataException("Unable to open repository: " + e.getMessage());
 
 			HsqlException he = (HsqlException) cause;
@@ -84,7 +86,7 @@ public class HSQLDBRepositoryFactory implements RepositoryFactory {
 
 		if (delay > SLOW_CONNECTION_THRESHOLD)
 			// This could be an indication of excessive repository use, or insufficient pool size
-			LOGGER.warn(String.format("Fetching repository connection from pool took %dms (threshold: %dms)"), delay, SLOW_CONNECTION_THRESHOLD);
+			LOGGER.warn(() -> String.format("Fetching repository connection from pool took %dms (threshold: %dms)", delay, SLOW_CONNECTION_THRESHOLD));
 
 		setupConnection(connection);
 		return connection;
@@ -112,8 +114,9 @@ public class HSQLDBRepositoryFactory implements RepositoryFactory {
 			this.connectionPool.close(0);
 
 			// Now that all connections are closed, create a dedicated connection to shut down repository
-			try (Connection connection = DriverManager.getConnection(this.connectionUrl)) {
-				connection.createStatement().execute("SHUTDOWN");
+			try (Connection connection = DriverManager.getConnection(this.connectionUrl);
+					Statement stmt = connection.createStatement()) {
+				stmt.execute("SHUTDOWN");
 			}
 		} catch (SQLException e) {
 			throw new DataException("Error during repository shutdown", e);

src/main/java/org/qora/repository/hsqldb/HSQLDBSaver.java

@@ -22,8 +22,8 @@ public class HSQLDBSaver {
 
 	private String table;
 
-	private List<String> columns = new ArrayList<String>();
-	private List<Object> objects = new ArrayList<Object>();
+	private List<String> columns = new ArrayList<>();
+	private List<Object> objects = new ArrayList<>();
 
 	/**
 	 * Construct a SaveHelper, using SQL Connection and table name.

src/main/java/org/qora/repository/hsqldb/HSQLDBVotingRepository.java

@@ -41,7 +41,7 @@ public class HSQLDBVotingRepository implements VotingRepository {
 				if (optionsResultSet == null)
 					return null;
 
-				List<PollOptionData> pollOptions = new ArrayList<PollOptionData>();
+				List<PollOptionData> pollOptions = new ArrayList<>();
 
 				// NOTE: do-while because checkedExecute() above has already called rs.next() for us
 				do {
@@ -112,7 +112,7 @@ public class HSQLDBVotingRepository implements VotingRepository {
 	@Override
 	public List<VoteOnPollData> getVotes(String pollName) throws DataException {
 		String sql = "SELECT voter, option_index FROM PollVotes WHERE poll_name = ?";
-		List<VoteOnPollData> votes = new ArrayList<VoteOnPollData>();
+		List<VoteOnPollData> votes = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, pollName)) {
 			if (resultSet == null)

src/main/java/org/qora/repository/hsqldb/transaction/HSQLDBArbitraryTransactionRepository.java

@@ -65,6 +65,7 @@ public class HSQLDBArbitraryTransactionRepository extends HSQLDBTransactionRepos
 			this.savePayments(transactionData.getSignature(), arbitraryTransactionData.getPayments());
 	}
 
+	@Override
 	public void delete(TransactionData transactionData) throws DataException {
 		ArbitraryTransactionData arbitraryTransactionData = (ArbitraryTransactionData) transactionData;
 

src/main/java/org/qora/repository/hsqldb/transaction/HSQLDBCreatePollTransactionRepository.java

@@ -36,7 +36,7 @@ public class HSQLDBCreatePollTransactionRepository extends HSQLDBTransactionRepo
 				if (optionsResultSet == null)
 					return null;
 
-				List<PollOptionData> pollOptions = new ArrayList<PollOptionData>();
+				List<PollOptionData> pollOptions = new ArrayList<>();
 
 				// NOTE: do-while because checkedExecute() above has already called rs.next() for us
 				do {

src/main/java/org/qora/repository/hsqldb/transaction/HSQLDBTransactionRepository.java

@@ -9,7 +9,7 @@ import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Calendar;
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.List;
 import java.util.Map;
 
@@ -105,16 +105,13 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 		for (TransactionType txType : TransactionType.values()) {
 			RepositorySubclassInfo subclassInfo = subclassInfos[txType.value];
 
-			if (subclassInfo == null)
-				continue;
-
-			if (subclassInfo.constructor == null)
+			if (subclassInfo == null || subclassInfo.constructor == null)
 				continue;
 
 			try {
 				this.repositoryByTxType[txType.value] = (HSQLDBTransactionRepository) subclassInfo.constructor.newInstance(repository);
 			} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException | InstantiationException e) {
-				continue;
+				LOGGER.debug(String.format("HSQLDBTransactionRepository subclass constructor failed for transaction type \"%s\"", txType.name()));
 			}
 		}
 	}
@@ -152,9 +149,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 				approvalHeight = null;
 
 			BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, txGroupId, reference, creatorPublicKey, fee, approvalStatus, blockHeight, approvalHeight, signature);
-			TransactionData transactionData = this.fromBase(type, baseTransactionData);
-
-			return transactionData;
+			return this.fromBase(type, baseTransactionData);
 		} catch (SQLException e) {
 			throw new DataException("Unable to fetch transaction from repository", e);
 		}
@@ -187,9 +182,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 				approvalHeight = null;
 
 			BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, txGroupId, reference, creatorPublicKey, fee, approvalStatus, blockHeight, approvalHeight, signature);
-			TransactionData transactionData = this.fromBase(type, baseTransactionData);
-
-			return transactionData;
+			return this.fromBase(type, baseTransactionData);
 		} catch (SQLException e) {
 			throw new DataException("Unable to fetch transaction from repository", e);
 		}
@@ -242,7 +235,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 	protected List<PaymentData> getPaymentsFromSignature(byte[] signature) throws DataException {
 		String sql = "SELECT recipient, amount, asset_id FROM SharedTransactionPayments WHERE signature = ?";
 
-		List<PaymentData> payments = new ArrayList<PaymentData>();
+		List<PaymentData> payments = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, signature)) {
 			if (resultSet == null)
@@ -314,7 +307,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 	public List<byte[]> getSignaturesInvolvingAddress(String address) throws DataException {
 		String sql = "SELECT signature FROM TransactionRecipients WHERE participant = ?";
 
-		List<byte[]> signatures = new ArrayList<byte[]>();
+		List<byte[]> signatures = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, address)) {
 			if (resultSet == null)
@@ -366,7 +359,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 			+ "WHERE block_height BETWEEN ? AND ? "
 			+ "GROUP BY type";
 
-		Map<TransactionType, Integer> transactionCounts = new HashMap<>();
+		Map<TransactionType, Integer> transactionCounts = new EnumMap<>(TransactionType.class);
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, startHeight, endHeight)) {
 			if (resultSet == null)
@@ -389,7 +382,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 	public List<byte[]> getSignaturesMatchingCriteria(Integer startBlock, Integer blockLimit, Integer txGroupId,
 			List<TransactionType> txTypes, Integer service, String address,
 			ConfirmationStatus confirmationStatus, Integer limit, Integer offset, Boolean reverse) throws DataException {
-		List<byte[]> signatures = new ArrayList<byte[]>();
+		List<byte[]> signatures = new ArrayList<>();
 
 		boolean hasAddress = address != null && !address.isEmpty();
 		boolean hasTxTypes = txTypes != null && !txTypes.isEmpty();
@@ -399,9 +392,9 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 			startBlock = (reverse == null || !reverse) ? 1 : this.repository.getBlockRepository().getBlockchainHeight() - blockLimit;
 
 		String signatureColumn = "Transactions.signature";
-		List<String> whereClauses = new ArrayList<String>();
+		List<String> whereClauses = new ArrayList<>();
 		String groupBy = null;
-		List<Object> bindParams = new ArrayList<Object>();
+		List<Object> bindParams = new ArrayList<>();
 
 		// Tables, starting with Transactions
 		StringBuilder tables = new StringBuilder(256);
@@ -579,7 +572,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString())) {
 			if (resultSet == null)
@@ -693,7 +686,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		// Find transactions with no corresponding row in BlockTransactions
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), bindParams)) {
@@ -729,7 +722,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 
 		sql.append(" AND Transactions.block_height < ? - Groups.min_block_delay");
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), blockHeight)) {
 			if (resultSet == null)
@@ -764,7 +757,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 
 		sql.append(" AND Transactions.block_height < ? - Groups.max_block_delay");
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), blockHeight)) {
 			if (resultSet == null)
@@ -925,7 +918,7 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 
 		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
 
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		// Find transactions with no corresponding row in BlockTransactions
 		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString())) {

src/main/java/org/qora/settings/Settings.java

@@ -94,8 +94,8 @@ public class Settings {
 
 	// Auto-update sources
 	private String[] autoUpdateRepos = new String[] {
-		"https://github.com/catbref/qora-core/raw/%s/qora-core.jar",
-		"https://[email protected]/catbref/qora-core/%s/qora-core.jar"
+		"https://github.com/QORT/qortal/raw/%s/qora-core.jar",
+		"https://[email protected]/QORT/qortal/%s/qora-core.jar"
 	};
 
 	/** Array of NTP server hostnames. */
@@ -171,7 +171,7 @@ public class Settings {
 		String path = "";
 
 		do {
-			LOGGER.info("Using settings file: " + path + filename);
+			LOGGER.info(String.format("Using settings file: %s%s", path, filename));
 
 			// Create the StreamSource by creating Reader to the JSON input
 			try (Reader settingsReader = new FileReader(path + filename)) {

src/main/java/org/qora/transaction/ArbitraryTransaction.java

@@ -35,7 +35,7 @@ public class ArbitraryTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() throws DataException {
-		List<Account> recipients = new ArrayList<Account>();
+		List<Account> recipients = new ArrayList<>();
 
 		if (arbitraryTransactionData.getVersion() != 1)
 			for (PaymentData paymentData : arbitraryTransactionData.getPayments())
@@ -92,7 +92,7 @@ public class ArbitraryTransaction extends Transaction {
 	@Override
 	public ValidationResult isValid() throws DataException {
 		// Are arbitrary transactions even allowed at this point?
-		if (arbitraryTransactionData.getVersion() != ArbitraryTransaction.getVersionByTimestamp(arbitraryTransactionData.getTimestamp()))
+		if (arbitraryTransactionData.getVersion() != Transaction.getVersionByTimestamp(arbitraryTransactionData.getTimestamp()))
 			return ValidationResult.NOT_YET_RELEASED;
 
 		if (this.arbitraryTransactionData.getTimestamp() < BlockChain.getInstance().getArbitraryReleaseTimestamp())

src/main/java/org/qora/transaction/AtTransaction.java

@@ -57,7 +57,7 @@ public class AtTransaction extends Transaction {
 	/** For AT-Transactions, the use the AT address instead of transaction creator (which is genesis account) */
 	@Override
 	public List<Account> getInvolvedAccounts() throws DataException {
-		List<Account> participants = new ArrayList<Account>(getRecipientAccounts());
+		List<Account> participants = new ArrayList<>(getRecipientAccounts());
 		participants.add(getATAccount());
 		return participants;
 	}

src/main/java/org/qora/transaction/CancelAssetOrderTransaction.java

@@ -33,7 +33,7 @@ public class CancelAssetOrderTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override

src/main/java/org/qora/transaction/CancelSellNameTransaction.java

@@ -33,7 +33,7 @@ public class CancelSellNameTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override

src/main/java/org/qora/transaction/CreateAssetOrderTransaction.java

@@ -35,7 +35,7 @@ public class CreateAssetOrderTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override

src/main/java/org/qora/transaction/DeployAtTransaction.java

@@ -1,9 +1,9 @@
 package org.qora.transaction;
 
-import java.io.UnsupportedEncodingException;
 import java.math.BigDecimal;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -46,7 +46,7 @@ public class DeployAtTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() throws DataException {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override
@@ -79,8 +79,7 @@ public class DeployAtTransaction extends Transaction {
 	/** Returns AT version from the header bytes */
 	private short getVersion() {
 		byte[] creationBytes = deployATTransactionData.getCreationBytes();
-		short version = (short) (creationBytes[0] | (creationBytes[1] << 8)); // Little-endian
-		return version;
+		return (short) ((creationBytes[0] & 0xff) | (creationBytes[1] << 8)); // Little-endian
 	}
 
 	/** Make sure deployATTransactionData has an ATAddress */
@@ -92,29 +91,25 @@ public class DeployAtTransaction extends Transaction {
 		if (blockHeight == 0)
 			blockHeight = this.repository.getBlockRepository().getBlockchainHeight() + 1;
 
-		try {
-			byte[] name = this.deployATTransactionData.getName().getBytes("UTF-8");
-			byte[] description = this.deployATTransactionData.getDescription().replaceAll("\\s", "").getBytes("UTF-8");
-			byte[] creatorPublicKey = this.deployATTransactionData.getCreatorPublicKey();
-			byte[] creationBytes = this.deployATTransactionData.getCreationBytes();
+		byte[] name = this.deployATTransactionData.getName().getBytes(StandardCharsets.UTF_8);
+		byte[] description = this.deployATTransactionData.getDescription().replaceAll("\\s", "").getBytes(StandardCharsets.UTF_8);
+		byte[] creatorPublicKey = this.deployATTransactionData.getCreatorPublicKey();
+		byte[] creationBytes = this.deployATTransactionData.getCreationBytes();
 
-			ByteBuffer byteBuffer = ByteBuffer
-					.allocate(name.length + description.length + creatorPublicKey.length + creationBytes.length + Transformer.INT_LENGTH);
+		ByteBuffer byteBuffer = ByteBuffer
+				.allocate(name.length + description.length + creatorPublicKey.length + creationBytes.length + Transformer.INT_LENGTH);
 
-			byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
+		byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
 
-			byteBuffer.put(name);
-			byteBuffer.put(description);
-			byteBuffer.put(creatorPublicKey);
-			byteBuffer.put(creationBytes);
-			byteBuffer.putInt(blockHeight);
+		byteBuffer.put(name);
+		byteBuffer.put(description);
+		byteBuffer.put(creatorPublicKey);
+		byteBuffer.put(creationBytes);
+		byteBuffer.putInt(blockHeight);
 
-			String atAddress = Crypto.toATAddress(byteBuffer.array());
+		String atAddress = Crypto.toATAddress(byteBuffer.array());
 
-			this.deployATTransactionData.setAtAddress(atAddress);
-		} catch (UnsupportedEncodingException e) {
-			throw new DataException("Unable to generate AT account from Deploy AT transaction data", e);
-		}
+		this.deployATTransactionData.setAtAddress(atAddress);
 	}
 
 	// Navigation

src/main/java/org/qora/transaction/MessageTransaction.java

@@ -90,7 +90,7 @@ public class MessageTransaction extends Transaction {
 	@Override
 	public ValidationResult isValid() throws DataException {
 		// Are message transactions even allowed at this point?
-		if (messageTransactionData.getVersion() != MessageTransaction.getVersionByTimestamp(messageTransactionData.getTimestamp()))
+		if (messageTransactionData.getVersion() != Transaction.getVersionByTimestamp(messageTransactionData.getTimestamp()))
 			return ValidationResult.NOT_YET_RELEASED;
 
 		if (this.repository.getBlockRepository().getBlockchainHeight() < BlockChain.getInstance().getMessageReleaseHeight())

src/main/java/org/qora/transaction/MultiPaymentTransaction.java

@@ -35,7 +35,7 @@ public class MultiPaymentTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() throws DataException {
-		List<Account> recipients = new ArrayList<Account>();
+		List<Account> recipients = new ArrayList<>();
 
 		for (PaymentData paymentData : multiPaymentTransactionData.getPayments())
 			recipients.add(new Account(this.repository, paymentData.getRecipient()));
@@ -95,7 +95,7 @@ public class MultiPaymentTransaction extends Transaction {
 			return ValidationResult.NOT_YET_RELEASED;
 
 		// Check number of payments
-		if (payments.size() < 1 || payments.size() > MAX_PAYMENTS_COUNT)
+		if (payments.isEmpty() || payments.size() > MAX_PAYMENTS_COUNT)
 			return ValidationResult.INVALID_PAYMENTS_COUNT;
 
 		// Check reference is correct

src/main/java/org/qora/transaction/SellNameTransaction.java

@@ -36,7 +36,7 @@ public class SellNameTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override

src/main/java/org/qora/transaction/Transaction.java

@@ -7,6 +7,7 @@ import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.locks.ReentrantLock;
@@ -91,7 +92,7 @@ public abstract class Transaction {
 		public final Class<?> clazz;
 		public final Constructor<?> constructor;
 
-		private final static Map<Integer, TransactionType> map = stream(TransactionType.values()).collect(toMap(type -> type.value, type -> type));
+		private static final Map<Integer, TransactionType> map = stream(TransactionType.values()).collect(toMap(type -> type.value, type -> type));
 
 		TransactionType(int value, boolean needsApproval) {
 			this.value = value;
@@ -105,14 +106,14 @@ public abstract class Transaction {
 
 			this.className = String.join("", classNameParts);
 
-			Class<?> clazz = null;
-			Constructor<?> constructor = null;
+			Class<?> subClazz = null;
+			Constructor<?> subConstructor = null;
 
 			try {
-				clazz = Class.forName(String.join("", Transaction.class.getPackage().getName(), ".", this.className, "Transaction"));
+				subClazz = Class.forName(String.join("", Transaction.class.getPackage().getName(), ".", this.className, "Transaction"));
 
 				try {
-					constructor = clazz.getConstructor(Repository.class, TransactionData.class);
+					subConstructor = subClazz.getConstructor(Repository.class, TransactionData.class);
 				} catch (NoSuchMethodException | SecurityException e) {
 					LOGGER.debug(String.format("Transaction subclass constructor not found for transaction type \"%s\"", this.name()));
 				}
@@ -120,8 +121,8 @@ public abstract class Transaction {
 				LOGGER.debug(String.format("Transaction subclass not found for transaction type \"%s\"", this.name()));
 			}
 
-			this.clazz = clazz;
-			this.constructor = constructor;
+			this.clazz = subClazz;
+			this.constructor = subConstructor;
 		}
 
 		public static TransactionType valueOf(int value) {
@@ -140,7 +141,7 @@ public abstract class Transaction {
 
 		public final int value;
 
-		private final static Map<Integer, ApprovalStatus> map = stream(ApprovalStatus.values()).collect(toMap(result -> result.value, result -> result));
+		private static final Map<Integer, ApprovalStatus> map = stream(ApprovalStatus.values()).collect(toMap(result -> result.value, result -> result));
 
 		ApprovalStatus(int value) {
 			this.value = value;
@@ -244,7 +245,7 @@ public abstract class Transaction {
 
 		public final int value;
 
-		private final static Map<Integer, ValidationResult> map = stream(ValidationResult.values()).collect(toMap(result -> result.value, result -> result));
+		private static final Map<Integer, ValidationResult> map = stream(ValidationResult.values()).collect(toMap(result -> result.value, result -> result));
 
 		ValidationResult(int value) {
 			this.value = value;
@@ -417,7 +418,7 @@ public abstract class Transaction {
 	 */
 	public List<Account> getInvolvedAccounts() throws DataException {
 		// Typically this is all the recipients plus the transaction creator/sender
-		List<Account> participants = new ArrayList<Account>(getRecipientAccounts());
+		List<Account> participants = new ArrayList<>(getRecipientAccounts());
 		participants.add(getCreator());
 		return participants;
 	}
@@ -622,8 +623,8 @@ public abstract class Transaction {
 		List<TransactionData> unconfirmedTransactions = repository.getTransactionRepository().getUnconfirmedTransactions();
 
 		int count = 0;
-		for (TransactionData transactionData : unconfirmedTransactions) {
-			Transaction transaction = Transaction.fromData(repository, transactionData);
+		for (TransactionData unconfirmedTransactionData : unconfirmedTransactions) {
+			Transaction transaction = Transaction.fromData(repository, unconfirmedTransactionData);
 			PublicKeyAccount otherCreator = transaction.getCreator();
 
 			if (Arrays.equals(creator.getPublicKey(), otherCreator.getPublicKey()))
@@ -662,14 +663,14 @@ public abstract class Transaction {
 			repository.discardChanges();
 
 			try {
-				for (int i = 0; i < unconfirmedTransactions.size(); ++i) {
-					TransactionData transactionData = unconfirmedTransactions.get(i);
+				Iterator<TransactionData> unconfirmedTransactionsIterator = unconfirmedTransactions.iterator();
+				while (unconfirmedTransactionsIterator.hasNext()) {
+					TransactionData transactionData = unconfirmedTransactionsIterator.next();
 
-					if (!isStillValidUnconfirmed(repository, transactionData, latestBlockData.getTimestamp())) {
-						unconfirmedTransactions.remove(i);
-						--i;
+					if (isStillValidUnconfirmed(repository, transactionData, latestBlockData.getTimestamp()))
 						continue;
-					}
+
+					unconfirmedTransactionsIterator.remove();
 				}
 			} finally {
 				// Throw away temporary updates to account lastReference
@@ -713,16 +714,15 @@ public abstract class Transaction {
 			repository.discardChanges();
 
 			try {
-				for (int i = 0; i < unconfirmedTransactions.size(); ++i) {
-					TransactionData transactionData = unconfirmedTransactions.get(i);
-
-					if (!isStillValidUnconfirmed(repository, transactionData, latestBlockData.getTimestamp())) {
-						invalidTransactions.add(transactionData);
+				Iterator<TransactionData> unconfirmedTransactionsIterator = unconfirmedTransactions.iterator();
+				while (unconfirmedTransactionsIterator.hasNext()) {
+					TransactionData transactionData = unconfirmedTransactionsIterator.next();
 
-						unconfirmedTransactions.remove(i);
-						--i;
+					if (isStillValidUnconfirmed(repository, transactionData, latestBlockData.getTimestamp()))
 						continue;
-					}
+
+					invalidTransactions.add(transactionData);
+					unconfirmedTransactionsIterator.remove();
 				}
 			} finally {
 				// Throw away temporary updates to account lastReference
@@ -927,7 +927,7 @@ public abstract class Transaction {
 	 */
 	public ValidationResult isProcessable() throws DataException {
 		return ValidationResult.OK;
-	};
+	}
 
 	/**
 	 * Actually process a transaction, updating the blockchain.

src/main/java/org/qora/transaction/VoteOnPollTransaction.java

@@ -41,7 +41,7 @@ public class VoteOnPollTransaction extends Transaction {
 
 	@Override
 	public List<Account> getRecipientAccounts() {
-		return new ArrayList<Account>();
+		return new ArrayList<>();
 	}
 
 	@Override
@@ -151,15 +151,13 @@ public class VoteOnPollTransaction extends Transaction {
 		Integer previousOptionIndex = voteOnPollTransactionData.getPreviousOptionIndex();
 		if (previousOptionIndex != null) {
 			// Reinstate previous vote
-			LOGGER.trace("Reinstating previous vote by " + voter.getAddress() + " on poll \"" + voteOnPollTransactionData.getPollName()
-					+ "\" with option index " + previousOptionIndex);
+			LOGGER.trace(() -> String.format("Reinstating previous vote by %s on poll \"%s\" with option index %d", voter.getAddress(), voteOnPollTransactionData.getPollName(), previousOptionIndex));
 			VoteOnPollData previousVoteOnPollData = new VoteOnPollData(voteOnPollTransactionData.getPollName(), voteOnPollTransactionData.getVoterPublicKey(),
 					previousOptionIndex);
 			votingRepository.save(previousVoteOnPollData);
 		} else {
 			// Delete vote
-			LOGGER.trace("Deleting vote by " + voter.getAddress() + " on poll \"" + voteOnPollTransactionData.getPollName() + "\" with option index "
-					+ voteOnPollTransactionData.getOptionIndex());
+			LOGGER.trace(() -> String.format("Deleting vote by %s on poll \"%s\" with option index %d", voter.getAddress(), voteOnPollTransactionData.getPollName(), voteOnPollTransactionData.getOptionIndex()));
 			votingRepository.delete(voteOnPollTransactionData.getPollName(), voteOnPollTransactionData.getVoterPublicKey());
 		}
 

src/main/java/org/qora/transform/PaymentTransformer.java

@@ -7,7 +7,6 @@ import java.nio.ByteBuffer;
 
 import org.json.simple.JSONObject;
 import org.qora.data.PaymentData;
-import org.qora.transform.TransformationException;
 import org.qora.utils.Serialization;
 
 import com.google.common.primitives.Longs;

src/main/java/org/qora/transform/block/BlockTransformer.java

@@ -109,7 +109,7 @@ public class BlockTransformer extends Transformer {
 
 		int atCount = 0;
 		BigDecimal atFees = BigDecimal.ZERO.setScale(8);
-		List<ATStateData> atStates = new ArrayList<ATStateData>();
+		List<ATStateData> atStates = new ArrayList<>();
 
 		if (version >= 2) {
 			int atBytesLength = byteBuffer.getInt();
@@ -172,7 +172,7 @@ public class BlockTransformer extends Transformer {
 		int transactionCount = byteBuffer.getInt();
 
 		// Parse transactions now, compared to deferred parsing in Gen1, so we can throw ParseException if need be.
-		List<TransactionData> transactions = new ArrayList<TransactionData>();
+		List<TransactionData> transactions = new ArrayList<>();
 
 		for (int t = 0; t < transactionCount; ++t) {
 			if (byteBuffer.remaining() < TRANSACTION_SIZE_LENGTH)
@@ -244,7 +244,7 @@ public class BlockTransformer extends Transformer {
 		BlockData blockData = new BlockData(version, reference, transactionCount, totalFees, transactionsSignature, height, timestamp,
 				generatorPublicKey, generatorSignature, atCount, atFees, encodedOnlineAccounts, onlineAccountsCount, onlineAccountsTimestamp, onlineAccountsSignatures);
 
-		return new Triple<BlockData, List<TransactionData>, List<ATStateData>>(blockData, transactions, atStates);
+		return new Triple<>(blockData, transactions, atStates);
 	}
 
 	public static int getDataLength(Block block) throws TransformationException {

src/main/java/org/qora/transform/transaction/ArbitraryTransactionTransformer.java

@@ -16,6 +16,7 @@ import org.qora.data.transaction.BaseTransactionData;
 import org.qora.data.transaction.TransactionData;
 import org.qora.data.transaction.ArbitraryTransactionData.DataType;
 import org.qora.transaction.ArbitraryTransaction;
+import org.qora.transaction.Transaction;
 import org.qora.transaction.Transaction.TransactionType;
 import org.qora.transform.PaymentTransformer;
 import org.qora.transform.TransformationException;
@@ -59,7 +60,7 @@ public class ArbitraryTransactionTransformer extends TransactionTransformer {
 	public static TransactionData fromByteBuffer(ByteBuffer byteBuffer) throws TransformationException {
 		long timestamp = byteBuffer.getLong();
 
-		int version = ArbitraryTransaction.getVersionByTimestamp(timestamp);
+		int version = Transaction.getVersionByTimestamp(timestamp);
 
 		int txGroupId = 0;
 		if (timestamp >= BlockChain.getInstance().getQoraV2Timestamp())
@@ -71,7 +72,7 @@ public class ArbitraryTransactionTransformer extends TransactionTransformer {
 		byte[] senderPublicKey = Serialization.deserializePublicKey(byteBuffer);
 
 		// V3+ allows payments but always return a list of payments, even if empty
-		List<PaymentData> payments = new ArrayList<PaymentData>();
+		List<PaymentData> payments = new ArrayList<>();
 		if (version != 1) {
 			int paymentsCount = byteBuffer.getInt();
 
@@ -182,7 +183,7 @@ public class ArbitraryTransactionTransformer extends TransactionTransformer {
 
 		// In v1, a coding error means that all bytes prior to final payment entry are lost!
 		// If there are no payments then we can skip mangling
-		if (arbitraryTransactionData.getPayments().size() == 0)
+		if (arbitraryTransactionData.getPayments().isEmpty())
 			return bytes;
 
 		// So we're left with: final payment entry, service, data size, data, fee

src/main/java/org/qora/transform/transaction/CreatePollTransactionTransformer.java

@@ -72,7 +72,7 @@ public class CreatePollTransactionTransformer extends TransactionTransformer {
 		if (optionsCount < 1 || optionsCount > Poll.MAX_OPTIONS)
 			throw new TransformationException("Invalid number of options for CreatePollTransaction");
 
-		List<PollOptionData> pollOptions = new ArrayList<PollOptionData>();
+		List<PollOptionData> pollOptions = new ArrayList<>();
 		for (int optionIndex = 0; optionIndex < optionsCount; ++optionIndex) {
 			String optionName = Serialization.deserializeSizedString(byteBuffer, Poll.MAX_NAME_SIZE);
 

src/main/java/org/qora/transform/transaction/DeployAtTransactionTransformer.java

@@ -11,6 +11,7 @@ import org.qora.data.transaction.BaseTransactionData;
 import org.qora.data.transaction.DeployAtTransactionData;
 import org.qora.data.transaction.TransactionData;
 import org.qora.transaction.DeployAtTransaction;
+import org.qora.transaction.Transaction;
 import org.qora.transaction.Transaction.TransactionType;
 import org.qora.transform.TransformationException;
 import org.qora.utils.Serialization;
@@ -59,7 +60,7 @@ public class DeployAtTransactionTransformer extends TransactionTransformer {
 	public static TransactionData fromByteBuffer(ByteBuffer byteBuffer) throws TransformationException {
 		long timestamp = byteBuffer.getLong();
 
-		int version = DeployAtTransaction.getVersionByTimestamp(timestamp);
+		int version = Transaction.getVersionByTimestamp(timestamp);
 
 		int txGroupId = 0;
 		if (timestamp >= BlockChain.getInstance().getQoraV2Timestamp())
@@ -106,7 +107,7 @@ public class DeployAtTransactionTransformer extends TransactionTransformer {
 
 		int dataLength = getBaseLength(transactionData) + EXTRAS_LENGTH;
 
-		int version = DeployAtTransaction.getVersionByTimestamp(transactionData.getTimestamp());
+		int version = Transaction.getVersionByTimestamp(transactionData.getTimestamp());
 
 		// V4+ have assetId too
 		if (version >= 4)
@@ -123,7 +124,7 @@ public class DeployAtTransactionTransformer extends TransactionTransformer {
 		try {
 			DeployAtTransactionData deployATTransactionData = (DeployAtTransactionData) transactionData;
 
-			int version = DeployAtTransaction.getVersionByTimestamp(transactionData.getTimestamp());
+			int version = Transaction.getVersionByTimestamp(transactionData.getTimestamp());
 
 			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
 

src/main/java/org/qora/transform/transaction/MessageTransactionTransformer.java

@@ -11,6 +11,7 @@ import org.qora.data.transaction.BaseTransactionData;
 import org.qora.data.transaction.MessageTransactionData;
 import org.qora.data.transaction.TransactionData;
 import org.qora.transaction.MessageTransaction;
+import org.qora.transaction.Transaction;
 import org.qora.transaction.Transaction.TransactionType;
 import org.qora.transform.TransformationException;
 import org.qora.utils.Serialization;
@@ -53,7 +54,7 @@ public class MessageTransactionTransformer extends TransactionTransformer {
 	public static TransactionData fromByteBuffer(ByteBuffer byteBuffer) throws TransformationException {
 		long timestamp = byteBuffer.getLong();
 
-		int version = MessageTransaction.getVersionByTimestamp(timestamp);
+		int version = Transaction.getVersionByTimestamp(timestamp);
 
 		int txGroupId = 0;
 		if (timestamp >= BlockChain.getInstance().getQoraV2Timestamp())

src/main/java/org/qora/transform/transaction/MultiPaymentTransactionTransformer.java

@@ -58,7 +58,7 @@ public class MultiPaymentTransactionTransformer extends TransactionTransformer {
 
 		int paymentsCount = byteBuffer.getInt();
 
-		List<PaymentData> payments = new ArrayList<PaymentData>();
+		List<PaymentData> payments = new ArrayList<>();
 		for (int i = 0; i < paymentsCount; ++i)
 			payments.add(PaymentTransformer.fromByteBuffer(byteBuffer));
 

src/main/java/org/qora/transform/transaction/UpdateAssetTransactionTransformer.java

@@ -80,11 +80,9 @@ public class UpdateAssetTransactionTransformer extends TransactionTransformer {
 	public static int getDataLength(TransactionData transactionData) throws TransformationException {
 		UpdateAssetTransactionData updateAssetTransactionData = (UpdateAssetTransactionData) transactionData;
 
-		int dataLength = getBaseLength(transactionData) + EXTRAS_LENGTH
+		return getBaseLength(transactionData) + EXTRAS_LENGTH
 				+ Utf8.encodedLength(updateAssetTransactionData.getNewDescription())
 				+ Utf8.encodedLength(updateAssetTransactionData.getNewData());
-
-		return dataLength;
 	}
 
 	public static byte[] toBytes(TransactionData transactionData) throws TransformationException {

src/main/java/org/qora/utils/BIP39.java

@@ -40,7 +40,7 @@ public class BIP39 {
 				bitShift = 0 - bitShift;
 				entropy[byteIndex++] |= (byte) (wordListIndex >> bitShift);
 
-				entropy[byteIndex] |= (byte) ((wordListIndex << (8 - bitShift)));
+				entropy[byteIndex] |= (byte) (wordListIndex << (8 - bitShift));
 				bitShift = bitShift + BITS_PER_WORD - 8;
 			}
 		}

src/main/java/org/qora/utils/ByteArray.java

@@ -27,7 +27,7 @@ public class ByteArray implements Comparable<ByteArray> {
 	public int hashCode() {
 		int h = hash;
 		if (h == 0 && value.length > 0) {
-			byte val[] = value;
+			byte[] val = value;
 
 			for (int i = 0; i < val.length; ++i)
 				h = 31 * h + val[i];
@@ -56,7 +56,7 @@ public class ByteArray implements Comparable<ByteArray> {
 			int b = otherValue[i] & 0xFF;
 			if (a < b)
 				return -1;
-			if (b > a)
+			if (a > b)
 				return 1;
 		}
 

src/main/java/org/qora/utils/NTP.java

@@ -53,7 +53,7 @@ public class NTP implements Runnable {
 			this.remote = remote;
 		}
 
-		public boolean poll(NTPUDPClient client) {
+		public boolean doPoll(NTPUDPClient client) {
 			Thread.currentThread().setName(String.format("NTP: %s", this.remote));
 
 			try {
@@ -161,9 +161,9 @@ public class NTP implements Runnable {
 			while (!isStopping) {
 				Thread.sleep(1000);
 
-				CompletionService<Boolean> ecs = new ExecutorCompletionService<Boolean>(serverExecutor);
+				CompletionService<Boolean> ecs = new ExecutorCompletionService<>(serverExecutor);
 				for (NTPServer server : ntpServers)
-					ecs.submit(() -> server.poll(client));
+					ecs.submit(() -> server.doPoll(client));
 
 				boolean hasUpdate = false;
 				for (int i = 0; i < ntpServers.size(); ++i) {

src/main/java/org/qora/utils/Serialization.java

@@ -6,6 +6,7 @@ import java.io.UnsupportedEncodingException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 
 import org.qora.transform.TransformationException;
 import org.qora.transform.Transformer;
@@ -92,7 +93,7 @@ public class Serialization {
 	}
 
 	public static void serializeSizedString(ByteArrayOutputStream bytes, String string) throws UnsupportedEncodingException, IOException {
-		byte[] stringBytes = string.getBytes("UTF-8");
+		byte[] stringBytes = string.getBytes(StandardCharsets.UTF_8);
 		bytes.write(Ints.toByteArray(stringBytes.length));
 		bytes.write(stringBytes);
 	}
@@ -108,11 +109,7 @@ public class Serialization {
 		byte[] bytes = new byte[size];
 		byteBuffer.get(bytes);
 
-		try {
-			return new String(bytes, "UTF-8");
-		} catch (UnsupportedEncodingException e) {
-			throw new TransformationException("UTF-8 charset unsupported during string deserialization");
-		}
+		return new String(bytes, StandardCharsets.UTF_8);
 	}
 
 }

src/main/java/org/qora/utils/StringLongMapXmlAdapter.java

@@ -16,7 +16,7 @@ public class StringLongMapXmlAdapter extends XmlAdapter<StringLongMapXmlAdapter.
 
 	public static class StringLongMap {
 		@XmlVariableNode("key")
-		List<MapEntry> entries = new ArrayList<MapEntry>();
+		List<MapEntry> entries = new ArrayList<>();
 	}
 
 	public static class MapEntry {

src/test/java/org/qora/test/ByteArrayTests.java

@@ -120,4 +120,14 @@ public class ByteArrayTests {
 		System.out.println(String.format("Primitive hashCode: 0x%08x", copiedValue.hashCode()));
 	}
 
+	@Test
+	public void testCompareTo() {
+		ByteArray testValue0 = new ByteArray(new byte[] { 0x00 });
+		ByteArray testValue1 = new ByteArray(new byte[] { 0x01 });
+
+		assertEquals("0 should be the same as 0", 0, testValue0.compareTo(testValue0));
+		assertEquals("0 should be before 1", -1, testValue0.compareTo(testValue1));
+		assertEquals("1 should be after 0", 1, testValue1.compareTo(testValue0));
+	}
+
 }