Code cleanup & improvements

- most notably removed some unnecessary synchronize blocks in the DefaultNetworkHandler

core/src/main/java/ch/dissem/bitmessage/BitmessageContext.java

@@ -302,9 +302,6 @@ public class BitmessageContext {
         long connectionTTL = 30 * MINUTE;
         boolean sendPubkeyOnIdentityCreation = true;
 
-        public Builder() {
-        }
-
         public Builder port(int port) {
             this.port = port;
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/Addr.java

@@ -55,9 +55,6 @@ public class Addr implements MessagePayload {
     public static final class Builder {
         private List<NetworkAddress> addresses = new ArrayList<NetworkAddress>();
 
-        public Builder() {
-        }
-
         public Builder addresses(Collection<NetworkAddress> addresses){
             this.addresses.addAll(addresses);
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/BitmessageAddress.java

@@ -188,7 +188,7 @@ public class BitmessageAddress implements Serializable {
 
     @Override
     public String toString() {
-        return alias != null ? alias : address;
+        return alias == null ? address : alias;
     }
 
     public byte[] getRipe() {

core/src/main/java/ch/dissem/bitmessage/entity/GetData.java

@@ -28,6 +28,8 @@ import java.util.List;
  * The 'getdata' command is used to request objects from a node.
  */
 public class GetData implements MessagePayload {
+    public static final int MAX_INVENTORY_SIZE = 50_000;
+
     List<InventoryVector> inventory;
 
     private GetData(Builder builder) {
@@ -54,9 +56,6 @@ public class GetData implements MessagePayload {
     public static final class Builder {
         private List<InventoryVector> inventory = new LinkedList<>();
 
-        public Builder() {
-        }
-
         public Builder addInventoryVector(InventoryVector inventoryVector) {
             this.inventory.add(inventoryVector);
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/Inv.java

@@ -54,9 +54,6 @@ public class Inv implements MessagePayload {
     public static final class Builder {
         private List<InventoryVector> inventory = new LinkedList<>();
 
-        public Builder() {
-        }
-
         public Builder addInventoryVector(InventoryVector inventoryVector) {
             this.inventory.add(inventoryVector);
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/ObjectMessage.java

@@ -156,10 +156,10 @@ public class ObjectMessage implements MessagePayload {
 
     @Override
     public void write(OutputStream out) throws IOException {
-        if (nonce != null) {
-            out.write(nonce);
-        } else {
+        if (nonce == null) {
             out.write(new byte[8]);
+        } else {
+            out.write(nonce);
         }
         out.write(getPayloadBytesWithoutNonce());
     }

core/src/main/java/ch/dissem/bitmessage/entity/Version.java

@@ -143,9 +143,6 @@ public class Version implements MessagePayload {
         private String userAgent;
         private long[] streamNumbers;
 
-        public Builder() {
-        }
-
         public Builder defaults() {
             version = BitmessageContext.CURRENT_VERSION;
             services = 1;

core/src/main/java/ch/dissem/bitmessage/entity/payload/V2Pubkey.java

@@ -96,9 +96,6 @@ public class V2Pubkey extends Pubkey {
         private byte[] publicSigningKey;
         private byte[] publicEncryptionKey;
 
-        public Builder() {
-        }
-
         public Builder stream(long streamNumber) {
             this.streamNumber = streamNumber;
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/payload/V3Pubkey.java

@@ -123,9 +123,6 @@ public class V3Pubkey extends V2Pubkey {
         private long extraBytes;
         private byte[] signature = new byte[0];
 
-        public Builder() {
-        }
-
         public Builder stream(long streamNumber) {
             this.streamNumber = streamNumber;
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/valueobject/NetworkAddress.java

@@ -134,9 +134,6 @@ public class NetworkAddress implements Streamable {
         private byte[] ipv6;
         private int port;
 
-        public Builder() {
-        }
-
         public Builder time(final long time) {
             this.time = time;
             return this;

core/src/main/java/ch/dissem/bitmessage/ports/SimplePOWEngine.java

@@ -20,6 +20,7 @@ import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.utils.Bytes;
 
 import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 
 import static ch.dissem.bitmessage.utils.Bytes.inc;
 
@@ -33,18 +34,17 @@ import static ch.dissem.bitmessage.utils.Bytes.inc;
 public class SimplePOWEngine implements ProofOfWorkEngine {
     @Override
     public void calculateNonce(byte[] initialHash, byte[] target, Callback callback) {
-        byte[] nonce = new byte[8];
-        MessageDigest mda;
         try {
-            mda = MessageDigest.getInstance("SHA-512");
-        } catch (Exception e) {
+            MessageDigest mda = MessageDigest.getInstance("SHA-512");
+            byte[] nonce = new byte[8];
+            do {
+                inc(nonce);
+                mda.update(nonce);
+                mda.update(initialHash);
+            } while (Bytes.lt(target, mda.digest(mda.digest()), 8));
+            callback.onNonceCalculated(initialHash, nonce);
+        } catch (NoSuchAlgorithmException e) {
             throw new ApplicationException(e);
         }
-        do {
-            inc(nonce);
-            mda.update(nonce);
-            mda.update(initialHash);
-        } while (Bytes.lt(target, mda.digest(mda.digest()), 8));
-        callback.onNonceCalculated(initialHash, nonce);
     }
 }