Fixed various warnings raised by the IDE.

src/main/java/org/qortal/api/resource/ArbitraryResource.java

@@ -41,7 +41,6 @@ import org.qortal.data.account.AccountData;
 import org.qortal.data.arbitrary.ArbitraryResourceInfo;
 import org.qortal.data.naming.NameData;
 import org.qortal.data.transaction.ArbitraryTransactionData;
-import org.qortal.data.transaction.ArbitraryTransactionData.*;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -185,13 +184,11 @@ public class ArbitraryResource {
 					service, name, 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));
 
 			return transactions;
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -331,7 +328,7 @@ public class ArbitraryResource {
 					   String path) {
 		Security.checkApiCallAllowed(request);
 
-		return this.upload(null, Service.valueOf(serviceString), name, null, path, null);
+		return this.upload(Service.valueOf(serviceString), name, null, path, null);
 	}
 
 	@POST
@@ -365,7 +362,7 @@ public class ArbitraryResource {
 					   		 String string) {
 		Security.checkApiCallAllowed(request);
 
-		return this.upload(null, Service.valueOf(serviceString), name, null, null, string);
+		return this.upload(Service.valueOf(serviceString), name, null, null, string);
 	}
 
 
@@ -401,7 +398,7 @@ public class ArbitraryResource {
 					   String path) {
 		Security.checkApiCallAllowed(request);
 
-		return this.upload(null, Service.valueOf(serviceString), name, identifier, path, null);
+		return this.upload(Service.valueOf(serviceString), name, identifier, path, null);
 	}
 
 	@POST
@@ -436,10 +433,10 @@ public class ArbitraryResource {
 							 String string) {
 		Security.checkApiCallAllowed(request);
 
-		return this.upload(null, Service.valueOf(serviceString), name, identifier, null, string);
+		return this.upload(Service.valueOf(serviceString), name, identifier, null, string);
 	}
 
-	private String upload(Method method, Service service, String name, String identifier, String path, String string) {
+	private String upload(Service service, String name, String identifier, String path, String string) {
 		// Fetch public key from registered name
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			NameData nameData = repository.getNameRepository().fromName(name);
@@ -473,7 +470,7 @@ public class ArbitraryResource {
 
 			try {
 				ArbitraryDataTransactionBuilder transactionBuilder = new ArbitraryDataTransactionBuilder(
-						publicKey58, Paths.get(path), name, method, service, identifier
+						publicKey58, Paths.get(path), name, null, service, identifier
 				);
 
 				transactionBuilder.build();
@@ -514,12 +511,11 @@ public class ArbitraryResource {
 					}
 
 					Thread.sleep(3000L);
-					continue;
 				}
 			}
 			java.nio.file.Path outputPath = arbitraryDataReader.getFilePath();
 
-			if (filepath == null || filepath.isEmpty()) {
+			if (filepath.isEmpty()) {
 				// No file path supplied - so check if this is a single file resource
 				String[] files = ArrayUtils.removeElement(outputPath.toFile().list(), ".qortal");
 				if (files.length == 1) {

src/main/java/org/qortal/api/resource/RenderResource.java

@@ -70,11 +70,10 @@ public class RenderResource {
     @SecurityRequirement(name = "apiKey")
     public String preview(String directoryPath) {
         Security.checkApiCallAllowed(request);
-        String name = null;
         Method method = Method.PUT;
         Compression compression = Compression.ZIP;
 
-        ArbitraryDataWriter arbitraryDataWriter = new ArbitraryDataWriter(Paths.get(directoryPath), name, Service.WEBSITE, null, method, compression);
+        ArbitraryDataWriter arbitraryDataWriter = new ArbitraryDataWriter(Paths.get(directoryPath), null, Service.WEBSITE, null, method, compression);
         try {
             arbitraryDataWriter.save();
         } catch (IOException | DataException | InterruptedException | MissingDataException e) {

src/main/java/org/qortal/arbitrary/ArbitraryDataBuildQueueItem.java

@@ -10,11 +10,11 @@ import java.io.IOException;
 
 public class ArbitraryDataBuildQueueItem {
 
-    private String resourceId;
+    private final String resourceId;
-    private ResourceIdType resourceIdType;
+    private final ResourceIdType resourceIdType;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
-    private Long creationTimestamp = null;
+    private final Long creationTimestamp;
     private Long buildStartTimestamp = null;
     private Long buildEndTimestamp = null;
     private boolean failed = false;

src/main/java/org/qortal/arbitrary/ArbitraryDataBuilder.java

@@ -19,22 +19,22 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
-import java.util.Objects;
 
 public class ArbitraryDataBuilder {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataBuilder.class);
 
-    private String name;
+    private final String name;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
 
     private boolean canRequestMissingFiles;
 
     private List<ArbitraryTransactionData> transactions;
     private ArbitraryTransactionData latestPutTransaction;
-    private List<Path> paths;
+    private final List<Path> paths;
     private byte[] latestSignature;
     private Path finalPath;
     private int layerCount;
@@ -118,7 +118,7 @@ public class ArbitraryDataBuilder {
 
         // Verify that the signature of the first transaction matches the latest PUT
         ArbitraryTransactionData firstTransaction = transactionDataList.get(0);
-        if (!Objects.equals(firstTransaction.getSignature(), latestPut.getSignature())) {
+        if (!Arrays.equals(firstTransaction.getSignature(), latestPut.getSignature())) {
             throw new IllegalStateException("First transaction did not match latest PUT transaction");
         }
 
@@ -126,9 +126,8 @@ public class ArbitraryDataBuilder {
         transactionDataList.remove(0);
 
         for (ArbitraryTransactionData transactionData : transactionDataList) {
-            if (!(transactionData instanceof ArbitraryTransactionData)) {
+            if (transactionData == null) {
-                String sig58 = Base58.encode(transactionData.getSignature());
+                throw new IllegalStateException("Transaction not found");
-                throw new IllegalStateException(String.format("Received non-arbitrary transaction: %s", sig58));
             }
             if (transactionData.getMethod() != Method.PATCH) {
                 throw new IllegalStateException("Expected PATCH but received PUT");
@@ -198,8 +197,8 @@ public class ArbitraryDataBuilder {
     }
 
     private void validatePaths() {
-        if (this.paths == null || this.paths.isEmpty()) {
+        if (this.paths.isEmpty()) {
-            throw new IllegalStateException(String.format("No paths available from which to build latest state"));
+            throw new IllegalStateException("No paths available from which to build latest state");
         }
     }
 
@@ -236,11 +235,15 @@ public class ArbitraryDataBuilder {
         this.finalPath = pathBefore;
     }
 
-    private void cacheLatestSignature() throws IOException {
+    private void cacheLatestSignature() throws IOException, DataException {
         byte[] latestTransactionSignature = this.transactions.get(this.transactions.size()-1).getSignature();
         if (latestTransactionSignature == null) {
             throw new IllegalStateException("Missing latest transaction signature");
         }
+        Long now = NTP.getTime();
+        if (now == null) {
+            throw new DataException("NTP time not synced yet");
+        }
 
         ArbitraryDataMetadataCache cache = new ArbitraryDataMetadataCache(this.finalPath);
         cache.setSignature(latestTransactionSignature);

src/main/java/org/qortal/arbitrary/ArbitraryDataCache.java

@@ -17,12 +17,12 @@ import java.util.Arrays;
 
 public class ArbitraryDataCache {
 
-    private boolean overwrite;
+    private final boolean overwrite;
-    private Path filePath;
+    private final Path filePath;
-    private String resourceId;
+    private final String resourceId;
-    private ResourceIdType resourceIdType;
+    private final ResourceIdType resourceIdType;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
 
     public ArbitraryDataCache(Path filePath, boolean overwrite, String resourceId,
                               ResourceIdType resourceIdType, Service service, String identifier) {
@@ -125,10 +125,7 @@ public class ArbitraryDataCache {
         }
 
         // Check if they match
-        if (!Arrays.equals(latestTransactionSig, cachedSig)) {
+        return !Arrays.equals(latestTransactionSig, cachedSig);
-            return true;
-        }
-        return false;
     }
 
     private byte[] fetchLatestTransactionSignature() {

src/main/java/org/qortal/arbitrary/ArbitraryDataCombiner.java

@@ -21,9 +21,9 @@ public class ArbitraryDataCombiner {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataCombiner.class);
 
-    private Path pathBefore;
+    private final Path pathBefore;
-    private Path pathAfter;
+    private final Path pathAfter;
-    private byte[] signatureBefore;
+    private final byte[] signatureBefore;
     private boolean shouldValidateHashes;
     private Path finalPath;
     private ArbitraryDataMetadataPatch metadata;
@@ -81,10 +81,10 @@ public class ArbitraryDataCombiner {
 
     private void preExecute() {
         if (this.pathBefore == null || this.pathAfter == null) {
-            throw new IllegalStateException(String.format("No paths available to build patch"));
+            throw new IllegalStateException("No paths available to build patch");
         }
         if (!Files.exists(this.pathBefore) || !Files.exists(this.pathAfter)) {
-            throw new IllegalStateException(String.format("Unable to create patch because at least one path doesn't exist"));
+            throw new IllegalStateException("Unable to create patch because at least one path doesn't exist");
         }
     }
 

src/main/java/org/qortal/arbitrary/ArbitraryDataCreatePatch.java

@@ -16,9 +16,9 @@ public class ArbitraryDataCreatePatch {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataCreatePatch.class);
 
-    private Path pathBefore;
+    private final Path pathBefore;
     private Path pathAfter;
-    private byte[] previousSignature;
+    private final byte[] previousSignature;
 
     private Path finalPath;
     private int totalFileCount;
@@ -50,10 +50,10 @@ public class ArbitraryDataCreatePatch {
 
     private void preExecute() {
         if (this.pathBefore == null || this.pathAfter == null) {
-            throw new IllegalStateException(String.format("No paths available to build patch"));
+            throw new IllegalStateException("No paths available to build patch");
         }
         if (!Files.exists(this.pathBefore) || !Files.exists(this.pathAfter)) {
-            throw new IllegalStateException(String.format("Unable to create patch because at least one path doesn't exist"));
+            throw new IllegalStateException("Unable to create patch because at least one path doesn't exist");
         }
 
         this.createRandomIdentifier();

src/main/java/org/qortal/arbitrary/ArbitraryDataDiff.java

@@ -17,7 +17,7 @@ import java.util.*;
 public class ArbitraryDataDiff {
 
     /** Only create a patch if both the before and after file sizes are within defined limit **/
-    private static long MAX_DIFF_FILE_SIZE = 100 * 1024L; // 100kiB
+    private static final long MAX_DIFF_FILE_SIZE = 100 * 1024L; // 100kiB
 
 
     public enum DiffType {
@@ -61,17 +61,17 @@ public class ArbitraryDataDiff {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataDiff.class);
 
-    private Path pathBefore;
+    private final Path pathBefore;
-    private Path pathAfter;
+    private final Path pathAfter;
-    private byte[] previousSignature;
+    private final byte[] previousSignature;
     private byte[] previousHash;
     private byte[] currentHash;
     private Path diffPath;
     private String identifier;
 
-    private List<Path> addedPaths;
+    private final List<Path> addedPaths;
-    private List<ModifiedPath> modifiedPaths;
+    private final List<ModifiedPath> modifiedPaths;
-    private List<Path> removedPaths;
+    private final List<Path> removedPaths;
 
     private int totalFileCount;
 
@@ -141,7 +141,7 @@ public class ArbitraryDataDiff {
             final ArbitraryDataDiff diff = this;
 
             // Check for additions or modifications
-            Files.walkFileTree(this.pathAfter, new FileVisitor<Path>() {
+            Files.walkFileTree(this.pathAfter, new FileVisitor<>() {
 
                 @Override
                 public FileVisitResult preVisitDirectory(Path after, BasicFileAttributes attrs) {
@@ -216,10 +216,10 @@ public class ArbitraryDataDiff {
             final ArbitraryDataDiff diff = this;
 
             // Check for removals
-            Files.walkFileTree(this.pathBefore, new FileVisitor<Path>() {
+            Files.walkFileTree(this.pathBefore, new FileVisitor<>() {
 
                 @Override
-                public FileVisitResult preVisitDirectory(Path before, BasicFileAttributes attrs) throws IOException {
+                public FileVisitResult preVisitDirectory(Path before, BasicFileAttributes attrs) {
                     Path directoryPathBefore = pathBeforeAbsolute.relativize(before.toAbsolutePath());
                     Path directoryPathAfter = pathAfterAbsolute.resolve(directoryPathBefore);
 
@@ -238,7 +238,7 @@ public class ArbitraryDataDiff {
                 }
 
                 @Override
-                public FileVisitResult visitFile(Path before, BasicFileAttributes attrs) throws IOException {
+                public FileVisitResult visitFile(Path before, BasicFileAttributes attrs) {
                     Path filePathBefore = pathBeforeAbsolute.relativize(before.toAbsolutePath());
                     Path filePathAfter = pathAfterAbsolute.resolve(filePathBefore);
 

src/main/java/org/qortal/arbitrary/ArbitraryDataDigest.java

@@ -1,7 +1,5 @@
 package org.qortal.arbitrary;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.qortal.utils.Base58;
 
 import java.io.IOException;
@@ -11,15 +9,12 @@ import java.nio.file.Path;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
 public class ArbitraryDataDigest {
 
-    private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataDigest.class);
+    private final Path path;
-
-    private Path path;
     private byte[] hash;
 
     public ArbitraryDataDigest(Path path) {
@@ -27,11 +22,10 @@ public class ArbitraryDataDigest {
     }
 
     public void compute() throws IOException {
-        List<Path> allPaths = Files.walk(path).filter(Files::isRegularFile).collect(Collectors.toList());
+        List<Path> allPaths = Files.walk(path).filter(Files::isRegularFile).sorted().collect(Collectors.toList());
-        Collections.sort(allPaths);
         Path basePathAbsolute = this.path.toAbsolutePath();
 
-        MessageDigest sha256 = null;
+        MessageDigest sha256;
         try {
             sha256 = MessageDigest.getInstance("SHA-256");
         } catch (NoSuchAlgorithmException e) {

src/main/java/org/qortal/arbitrary/ArbitraryDataFileChunk.java

@@ -6,8 +6,6 @@ import org.qortal.utils.Base58;
 
 import java.io.IOException;
 import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
 
 
 public class ArbitraryDataFileChunk extends ArbitraryDataFile {

src/main/java/org/qortal/arbitrary/ArbitraryDataMerge.java

@@ -20,8 +20,8 @@ public class ArbitraryDataMerge {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataMerge.class);
 
-    private Path pathBefore;
+    private final Path pathBefore;
-    private Path pathAfter;
+    private final Path pathAfter;
     private Path mergePath;
     private String identifier;
     private ArbitraryDataMetadataPatch metadata;

src/main/java/org/qortal/arbitrary/ArbitraryDataReader.java

@@ -41,19 +41,18 @@ public class ArbitraryDataReader {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataReader.class);
 
-    private String resourceId;
+    private final String resourceId;
-    private ResourceIdType resourceIdType;
+    private final ResourceIdType resourceIdType;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
     private ArbitraryTransactionData transactionData;
     private String secret58;
     private Path filePath;
     private boolean canRequestMissingFiles;
 
     // Intermediate paths
-    private Path workingPath;
+    private final Path workingPath;
-    private Path uncompressedPath;
+    private final Path uncompressedPath;
-    private Path unencryptedPath;
 
     // Stats (available for synchronous builds only)
     private int layerCount;
@@ -66,7 +65,7 @@ public class ArbitraryDataReader {
         }
 
         // If identifier is a blank string, treat it as null
-        if (identifier == "") {
+        if (identifier == null || identifier.equals("")) {
             identifier = null;
         }
 
@@ -116,8 +115,7 @@ public class ArbitraryDataReader {
      * This adds the build task to a queue, and the result will be cached when complete
      * To check the status of the build, periodically call isCachedDataAvailable()
      * Once it returns true, you can then use getFilePath() to access the data itself.
-     * TODO: create API to check the status
+     * @return true if added or already present in queue; false if not
-     * @return
      */
     public boolean loadAsynchronously() {
         ArbitraryDataBuildQueueItem queueItem =
@@ -136,6 +134,7 @@ public class ArbitraryDataReader {
      * @throws IllegalStateException
      * @throws IOException
      * @throws DataException
+     * @throws MissingDataException
      */
     public void loadSynchronously(boolean overwrite) throws IllegalStateException, IOException, DataException, MissingDataException {
         try {
@@ -195,7 +194,7 @@ public class ArbitraryDataReader {
             if (Files.exists(uncompressedPath)) {
                 LOGGER.trace("Attempting to delete path {}", this.uncompressedPath);
                 try {
-                    Files.walkFileTree(uncompressedPath, new SimpleFileVisitor<Path>() {
+                    Files.walkFileTree(uncompressedPath, new SimpleFileVisitor<>() {
 
                         @Override
                         public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
@@ -290,7 +289,7 @@ public class ArbitraryDataReader {
         try (final Repository repository = RepositoryManager.getRepository()) {
             transactionData = (ArbitraryTransactionData) repository.getTransactionRepository().fromSignature(Base58.decode(resourceId));
         }
-        if (!(transactionData instanceof ArbitraryTransactionData)) {
+        if (transactionData == null) {
             throw new IllegalStateException(String.format("Transaction data not found for signature %s", this.resourceId));
         }
 
@@ -298,7 +297,7 @@ public class ArbitraryDataReader {
     }
 
     private void fetchFromTransactionData(ArbitraryTransactionData transactionData) throws IllegalStateException, IOException, MissingDataException {
-        if (!(transactionData instanceof ArbitraryTransactionData)) {
+        if (transactionData == null) {
             throw new IllegalStateException(String.format("Transaction data not found for signature %s", this.resourceId));
         }
 
@@ -364,13 +363,13 @@ public class ArbitraryDataReader {
         byte[] secret = this.secret58 != null ? Base58.decode(this.secret58) : null;
         if (secret != null && secret.length == Transformer.AES256_LENGTH) {
             try {
-                this.unencryptedPath = Paths.get(this.workingPath.toString() + File.separator + "zipped.zip");
+                Path unencryptedPath = Paths.get(this.workingPath.toString() + File.separator + "zipped.zip");
                 SecretKey aesKey = new SecretKeySpec(secret, 0, secret.length, "AES");
-                AES.decryptFile("AES", aesKey, this.filePath.toString(), this.unencryptedPath.toString());
+                AES.decryptFile("AES", aesKey, this.filePath.toString(), unencryptedPath.toString());
 
                 // Replace filePath pointer with the encrypted file path
                 // Don't delete the original ArbitraryDataFile, as this is handled in the cleanup phase
-                this.filePath = this.unencryptedPath;
+                this.filePath = unencryptedPath;
 
             } catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException | NoSuchPaddingException
                     | BadPaddingException | IllegalBlockSizeException | IOException | InvalidKeyException e) {
@@ -454,12 +453,9 @@ public class ArbitraryDataReader {
         if (this.filePath.compareTo(this.uncompressedPath) != 0) {
             File source = new File(this.filePath.toString());
             File dest = new File(this.uncompressedPath.toString());
-            if (source == null || !source.exists()) {
+            if (!source.exists()) {
                 throw new IllegalStateException("Source directory doesn't exist");
             }
-            if (dest == null) {
-                throw new IllegalStateException("Destination is null");
-            }
             // Ensure destination directory doesn't exist
             FileUtils.deleteDirectory(dest);
             // Move files to destination
@@ -515,7 +511,7 @@ public class ArbitraryDataReader {
      * Use the below setter to ensure that we only read existing
      * data without requesting any missing files,
      *
-     * @param canRequestMissingFiles
+     * @param canRequestMissingFiles - whether or not fetching missing files is allowed
      */
     public void setCanRequestMissingFiles(boolean canRequestMissingFiles) {
         this.canRequestMissingFiles = canRequestMissingFiles;

src/main/java/org/qortal/arbitrary/ArbitraryDataRenderer.java

@@ -27,17 +27,17 @@ public class ArbitraryDataRenderer {
 
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataRenderer.class);
 
-    private String resourceId;
+    private final String resourceId;
-    private ResourceIdType resourceIdType;
+    private final ResourceIdType resourceIdType;
-    private Service service;
+    private final Service service;
     private String inPath;
-    private String secret58;
+    private final String secret58;
-    private String prefix;
+    private final String prefix;
-    private boolean usePrefix;
+    private final boolean usePrefix;
-    private boolean async;
+    private final boolean async;
-    private HttpServletRequest request;
+    private final HttpServletRequest request;
-    private HttpServletResponse response;
+    private final HttpServletResponse response;
-    private ServletContext context;
+    private final ServletContext context;
 
     public ArbitraryDataRenderer(String resourceId, ResourceIdType resourceIdType, Service service, String inPath,
                                  String secret58, String prefix, boolean usePrefix, boolean async,
@@ -77,12 +77,12 @@ public class ArbitraryDataRenderer {
 
         } catch (Exception e) {
             LOGGER.info(String.format("Unable to load %s %s: %s", service, resourceId, e.getMessage()));
-            return this.getResponse(response, 500, "Error 500: Internal Server Error");
+            return ArbitraryDataRenderer.getResponse(response, 500, "Error 500: Internal Server Error");
         }
 
         java.nio.file.Path path = arbitraryDataReader.getFilePath();
         if (path == null) {
-            return this.getResponse(response, 404, "Error 404: File Not Found");
+            return ArbitraryDataRenderer.getResponse(response, 404, "Error 404: File Not Found");
         }
         String unzippedPath = path.toString();
 
@@ -128,7 +128,7 @@ public class ArbitraryDataRenderer {
             LOGGER.info("Unable to serve file at path: {}", inPath, e);
         }
 
-        return this.getResponse(response, 404, "Error 404: File Not Found");
+        return ArbitraryDataRenderer.getResponse(response, 404, "Error 404: File Not Found");
     }
 
     private String getFilename(String directory, String userPath) {
@@ -146,14 +146,14 @@ public class ArbitraryDataRenderer {
     }
 
     private HttpServletResponse getLoadingResponse() {
-        String responseString = null;
+        String responseString = "";
         URL url = Resources.getResource("loading/index.html");
         try {
             responseString = Resources.toString(url, StandardCharsets.UTF_8);
         } catch (IOException e) {
             LOGGER.info("Unable to show loading screen: {}", e.getMessage());
         }
-        return this.getResponse(response, 503, responseString);
+        return ArbitraryDataRenderer.getResponse(response, 503, responseString);
     }
 
     public static HttpServletResponse getResponse(HttpServletResponse response, int responseCode, String responseString) {

src/main/java/org/qortal/arbitrary/ArbitraryDataResource.java

@@ -12,10 +12,10 @@ import java.io.IOException;
 
 public class ArbitraryDataResource {
 
-    private String resourceId;
+    private final String resourceId;
-    private ResourceIdType resourceIdType;
+    private final ResourceIdType resourceIdType;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
 
     public ArbitraryDataResource(String resourceId, ResourceIdType resourceIdType, Service service, String identifier) {
         this.resourceId = resourceId;

src/main/java/org/qortal/arbitrary/ArbitraryDataTransactionBuilder.java

@@ -42,12 +42,12 @@ public class ArbitraryDataTransactionBuilder {
     // Maximum proportion of files modified relative to total
     private static final double MAX_FILE_DIFF = 0.5f;
 
-    private String publicKey58;
+    private final String publicKey58;
-    private Path path;
+    private final Path path;
-    private String name;
+    private final String name;
     private Method method;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
 
     private ArbitraryTransactionData arbitraryTransactionData;
 
@@ -137,11 +137,14 @@ public class ArbitraryDataTransactionBuilder {
         ArbitraryDataFile arbitraryDataFile = null;
         try (final Repository repository = RepositoryManager.getRepository()) {
             Long now = NTP.getTime();
+            if (now == null) {
+                throw new DataException("NTP time not synced yet");
+            }
 
             // Ensure that this chain supports transactions necessary for complex arbitrary data
             int transactionVersion = Transaction.getVersionByTimestamp(now);
             if (transactionVersion < MIN_TRANSACTION_VERSION) {
-                throw new DataException(String.format("Transaction version unsupported on this blockchain."));
+                throw new DataException("Transaction version unsupported on this blockchain.");
             }
 
             if (publicKey58 == null || path == null) {

src/main/java/org/qortal/arbitrary/ArbitraryDataWriter.java

@@ -33,11 +33,11 @@ public class ArbitraryDataWriter {
     private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataWriter.class);
 
     private Path filePath;
-    private String name;
+    private final String name;
-    private Service service;
+    private final Service service;
-    private String identifier;
+    private final String identifier;
-    private Method method;
+    private final Method method;
-    private Compression compression;
+    private final Compression compression;
 
     private SecretKey aesKey;
     private ArbitraryDataFile arbitraryDataFile;

src/main/java/org/qortal/arbitrary/misc/Service.java

@@ -1,7 +1,5 @@
 package org.qortal.arbitrary.misc;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.json.JSONObject;
 import org.qortal.transaction.Transaction;
 
@@ -36,8 +34,6 @@ public enum Service {
     private final Long maxSize;
     private final List<String> requiredKeys;
 
-    private static final Logger LOGGER = LogManager.getLogger(Service.class);
-
     private static final Map<Integer, Service> map = stream(Service.values())
             .collect(toMap(service -> service.value, service -> service));
 

src/main/java/org/qortal/arbitrary/patch/UnifiedDiffPatch.java

@@ -26,9 +26,9 @@ public class UnifiedDiffPatch {
 
     private static final Logger LOGGER = LogManager.getLogger(UnifiedDiffPatch.class);
 
-    private Path before;
+    private final Path before;
-    private Path after;
+    private final Path after;
-    private Path destination;
+    private final Path destination;
 
     private String identifier;
     private Path validationPath;
@@ -95,7 +95,6 @@ public class UnifiedDiffPatch {
      * it works correctly and is smaller than the original file
      *
      * @return true if valid, false if invalid
-     * @throws IOException
      */
     public boolean isValid() {
         this.createRandomIdentifier();