Makes fields used for synchronization final

While these fields don't change on this code and, therefore, the
synchronization should be safe, adding marking them as final adds one
extra layer of protection to ensure their references won't be mistakenly
reassigned in future code changes

Signed-off-by: Otavio R. Piske <angusyoung@gmail.com>

Author: orpiske

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/BasicTest.java

@@ -502,7 +502,7 @@ public void test402a() throws Exception {
    */
   class MessageListener implements MqttCallback {
 
-    ArrayList<MqttMessage> messages;
+    final ArrayList<MqttMessage> messages;
 
     public MessageListener() {
       messages = new ArrayList<MqttMessage>();

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/LiveTakeOverTest.java

@@ -193,7 +193,7 @@ public void testLiveTakeOver() throws Exception {
   class FirstClient implements Runnable {
 
     private FirstClientState state = FirstClientState.INITIAL;
-    public Object stateLock = new Object();
+    public final Object stateLock = new Object();
     IMqttClient mqttClient = null;
     MqttV3Receiver mqttV3Receiver = null;
 

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/PerSubscriptionMessageHandlerTest.java

@@ -93,7 +93,7 @@ public static void tearDownAfterClass() throws Exception {
 
 	  class listener implements IMqttMessageListener {
 
-		  ArrayList<MqttMessage> messages;
+		  final ArrayList<MqttMessage> messages;
 
 		  public listener() {
 			  messages = new ArrayList<MqttMessage>();

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/SendReceiveAsyncCallbackTest.java

@@ -128,7 +128,7 @@ public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
 
 	class listener implements IMqttMessageListener {
 
-		ArrayList<MqttMessage> messages;
+		final ArrayList<MqttMessage> messages;
 
 		public listener() {
 			messages = new ArrayList<MqttMessage>();

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/WebSocketTest.java

@@ -306,7 +306,7 @@ public void testBasicAuth() throws Exception {
    */
   class MessageListener implements MqttCallback {
 
-    ArrayList<MqttMessage> messages;
+    final ArrayList<MqttMessage> messages;
 
     public MessageListener() {
       messages = new ArrayList<MqttMessage>();

org.eclipse.paho.client.mqttv3.test/src/test/java/org/eclipse/paho/client/mqttv3/test/utilities/ConnectionManipulationProxyServer.java

@@ -16,7 +16,7 @@ public class ConnectionManipulationProxyServer implements Runnable {
 	private String host;
 	private int remotePort;
 	private Thread proxyThread;
-	private Object enableLock = new Object();
+	private final Object enableLock = new Object();
 	private boolean enableProxy = true;
 	private boolean running = true;
 	Socket client = null, server = null;

org.eclipse.paho.client.mqttv3/src/main/java-templates/org/eclipse/paho/client/mqttv3/internal/ClientComms.java

@@ -79,7 +79,7 @@ public class ClientComms {
 	private boolean 				stoppingComms = false;
 
 	private byte	conState = DISCONNECTED;
-	private Object	conLock = new Object();  	// Used to synchronize connection state
+	private final Object	conLock = new Object();  	// Used to synchronize connection state
 	private boolean	closePending = false;
 	private boolean resting = false;
 	private DisconnectedMessageBuffer disconnectedMessageBuffer;

org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/MqttAsyncClient.java

@@ -111,7 +111,7 @@ public class MqttAsyncClient implements IMqttAsyncClient {
 	private static int reconnectDelay = 1000; // Reconnect delay, starts at 1
 												// second
 	private boolean reconnecting = false;
-	private static Object clientLock = new Object(); // Simple lock
+	private static final Object clientLock = new Object(); // Simple lock
 
 	private ScheduledExecutorService executorService;
 

org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/internal/ClientState.java

@@ -127,15 +127,15 @@ public class ClientState {
 	private int actualInFlight = 0;
 	private int inFlightPubRels = 0;
 
-	private Object queueLock = new Object();
-	private Object quiesceLock = new Object();
+	private final Object queueLock = new Object();
+	private final Object quiesceLock = new Object();
 	private boolean quiescing = false;
 
 	private long lastOutboundActivity = 0;
 	private long lastInboundActivity = 0;
 	private long lastPing = 0;
 	private MqttWireMessage pingCommand;
-	private Object pingOutstandingLock = new Object();
+	private final Object pingOutstandingLock = new Object();
 	private int pingOutstanding = 0;
 
 	private boolean connected = false;

org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/internal/CommsCallback.java

@@ -54,19 +54,19 @@ public class CommsCallback implements Runnable {
 	private MqttCallbackExtended reconnectInternalCallback;
 	private Hashtable<String, IMqttMessageListener> callbacks; // topicFilter -> messageHandler
 	private ClientComms clientComms;
-	private Vector<MqttWireMessage> messageQueue;
-	private Vector<MqttToken> completeQueue;
+	private final Vector<MqttWireMessage> messageQueue;
+	private final Vector<MqttToken> completeQueue;
 
 	private enum State {STOPPED, RUNNING, QUIESCING};
 	private State current_state = State.STOPPED;
 	private State target_state = State.STOPPED;
-	private Object lifecycle = new Object();
+	private final Object lifecycle = new Object();
 	private Thread callbackThread;
 	private String threadName;
 	private Future<?> callbackFuture;
 
-	private Object workAvailable = new Object();
-	private Object spaceAvailable = new Object();
+	private final Object workAvailable = new Object();
+	private final Object spaceAvailable = new Object();
 	private ClientState clientState;
 	private boolean manualAcks = false;