Introduce little code simplifications.

core/src/main/java/org/bitcoinj/core/Block.java

@@ -836,10 +836,8 @@ public class Block extends Message {
     public Sha256Hash getMerkleRoot() {
         maybeParseHeader();
         if (merkleRoot == null) {
-
             //TODO check if this is really necessary.
             unCacheHeader();
-
             merkleRoot = calculateMerkleRoot();
         }
         return merkleRoot;

core/src/main/java/org/bitcoinj/core/FilteredBlock.java

@@ -109,7 +109,7 @@ public class FilteredBlock extends Message {
         if (getTransactionHashes().contains(hash)) {
             associatedTransactions.put(hash, tx);
             return true;
-        } else
+        }
         return false;
     }
 
@@ -152,9 +152,6 @@ public class FilteredBlock extends Message {
 
     @Override
     public String toString() {
-        return "FilteredBlock{" +
+        return "FilteredBlock{merkleTree=" + merkleTree + ", header=" + header + '}';
-                "merkleTree=" + merkleTree +
-                ", header=" + header +
-                '}';
     }
 }

core/src/main/java/org/bitcoinj/core/InventoryItem.java

@@ -38,7 +38,6 @@ public class InventoryItem {
         this.hash = hash;
     }
 
-
     @Override
     public String toString() {
         return type.toString() + ": " + hash;

core/src/main/java/org/bitcoinj/core/TransactionInput.java

@@ -57,7 +57,7 @@ public class TransactionInput extends ChildMessage implements Serializable {
     private byte[] scriptBytes;
     // The Script object obtained from parsing scriptBytes. Only filled in on demand and if the transaction is not
     // coinbase.
-    transient private WeakReference<Script> scriptSig;
+    private transient WeakReference<Script> scriptSig;
     /** Value of the output connected to the input, if known. This field does not participate in equals()/hashCode(). */
     @Nullable
     private Coin value;
@@ -177,7 +177,6 @@ public class TransactionInput extends ChildMessage implements Serializable {
             maybeParse();
             script = new Script(scriptBytes);
             scriptSig = new WeakReference<Script>(script);
-            return script;
         }
         return script;
     }

core/src/main/java/org/bitcoinj/core/TransactionOutput.java

@@ -206,8 +206,9 @@ public class TransactionOutput extends ChildMessage implements Serializable {
      * over the parents list to discover this.
      */
     public int getIndex() {
-        for (int i = 0; i < getParentTransaction().getOutputs().size(); i++) {
+        List<TransactionOutput> outputs = getParentTransaction().getOutputs();
-            if (getParentTransaction().getOutputs().get(i) == this)
+        for (int i = 0; i < outputs.size(); i++) {
+            if (outputs.get(i) == this)
                 return i;
         }
         throw new IllegalStateException("Output linked to wrong parent transaction?");
@@ -256,7 +257,7 @@ public class TransactionOutput extends ChildMessage implements Serializable {
         availableForSpending = false;
         spentBy = input;
         if (parent != null)
-            if (log.isDebugEnabled()) log.debug("Marked {}:{} as spent by {}", getParentTransaction().getHash(), getIndex(), input);
+            if (log.isDebugEnabled()) log.debug("Marked {}:{} as spent by {}", getParentTransactionHash(), getIndex(), input);
         else
             if (log.isDebugEnabled()) log.debug("Marked floating output as spent by {}", input);
     }
@@ -266,7 +267,7 @@ public class TransactionOutput extends ChildMessage implements Serializable {
      */
     public void markAsUnspent() {
         if (parent != null)
-            if (log.isDebugEnabled()) log.debug("Un-marked {}:{} as spent by {}", getParentTransaction().getHash(), getIndex(), spentBy);
+            if (log.isDebugEnabled()) log.debug("Un-marked {}:{} as spent by {}", getParentTransactionHash(), getIndex(), spentBy);
         else
             if (log.isDebugEnabled()) log.debug("Un-marked floating output as spent by {}", spentBy);
         availableForSpending = true;
@@ -374,21 +375,15 @@ public class TransactionOutput extends ChildMessage implements Serializable {
      */
     @Nullable
     public Transaction getParentTransaction() {
-        if(parent != null) {
         return (Transaction)parent;
     }
-        return null;
-    }
 
     /**
      * Returns the transaction hash that owns this output.
      */
     @Nullable
     public Sha256Hash getParentTransactionHash() {
-        if (getParentTransaction() != null) {
+        return parent == null ? null : parent.getHash();
-            return getParentTransaction().getHash();
-        }
-        return null;
     }
 
     /**

core/src/main/java/org/bitcoinj/core/UTXO.java

@@ -191,12 +191,6 @@ public class UTXO implements Serializable {
         bos.write(0xFF & (height >> 16));
         bos.write(0xFF & (height >> 24));
 
-        byte[] coinbaseByte = new byte[1];
+        bos.write(new byte[] { (byte)(coinbase ? 1 : 0) });
-        if (coinbase) {
-            coinbaseByte[0] = 1;
-        } else {
-            coinbaseByte[0] = 0;
-        }
-        bos.write(coinbaseByte);
     }
 }

core/src/main/java/org/bitcoinj/utils/ListenerRegistration.java

@@ -44,11 +44,6 @@ public class ListenerRegistration<T> {
                 break;
             }
         }
-        if (item != null) {
+        return item != null && list.remove(item);
-            list.remove(item);
-            return true;
-        } else {
-            return false;
-        }
     }
 }

core/src/main/java/org/bitcoinj/wallet/DeterministicSeed.java

@@ -45,8 +45,8 @@ public class DeterministicSeed implements EncryptableItem {
     public static final int MAX_SEED_ENTROPY_BITS = 512;
 
     @Nullable private final byte[] seed;
-    @Nullable private List<String> mnemonicCode;
+    @Nullable private final List<String> mnemonicCode; // only one of mnemonicCode/encryptedMnemonicCode will be set
-    @Nullable private EncryptedData encryptedMnemonicCode;
+    @Nullable private final EncryptedData encryptedMnemonicCode;
     @Nullable private EncryptedData encryptedSeed;
     private final long creationTimeSeconds;
 
@@ -135,17 +135,13 @@ public class DeterministicSeed implements EncryptableItem {
         if (isEncrypted())
             return "DeterministicSeed [encrypted]";
         else
-            return "DeterministicSeed " + toHexString() +
+            return "DeterministicSeed " + toHexString() + " " + Joiner.on(" ").join(mnemonicCode);
-                    ((mnemonicCode != null) ? " " + Joiner.on(" ").join(mnemonicCode) : "");
     }
 
     /** Returns the seed as hex or null if encrypted. */
     @Nullable
     public String toHexString() {
-        if (seed != null)
+        return seed != null ? HEX.encode(seed) : null;
-            return HEX.encode(seed);
-        else
-            return null;
     }
 
     @Nullable