Make bunch of private fields final

artemis-jdbc-store/src/main/java/org/apache/activemq/artemis/jdbc/store/file/JDBCSequentialFile.java

@@ -53,16 +53,16 @@ public class JDBCSequentialFile implements SequentialFile {
 
    private long writePosition = 0;
 
-   private Executor executor;
+   private final Executor executor;
 
-   private JDBCSequentialFileFactory fileFactory;
+   private final JDBCSequentialFileFactory fileFactory;
 
    private final Object writeLock;
 
    private final JDBCSequentialFileFactoryDriver dbDriver;
 
    // Allows DB Drivers to cache meta data.
-   private Map<Object, Object> metaData = new ConcurrentHashMap<>();
+   private final Map<Object, Object> metaData = new ConcurrentHashMap<>();
 
    public JDBCSequentialFile(final JDBCSequentialFileFactory fileFactory,
                              final String filename,

artemis-jdbc-store/src/main/java/org/apache/activemq/artemis/jdbc/store/file/JDBCSequentialFileFactory.java

@@ -39,11 +39,11 @@ public class JDBCSequentialFileFactory implements SequentialFileFactory, ActiveM
 
    private boolean started;
 
-   private List<JDBCSequentialFile> files;
+   private final List<JDBCSequentialFile> files = new ArrayList<>();
 
-   private Executor executor;
+   private final Executor executor;
 
-   private Map<String, Object> fileLocks = new HashMap<>();
+   private final Map<String, Object> fileLocks = new HashMap<>();
 
    private final JDBCSequentialFileFactoryDriver dbDriver;
 
@@ -52,7 +52,6 @@ public class JDBCSequentialFileFactory implements SequentialFileFactory, ActiveM
                                     final String tableName,
                                     Executor executor) throws Exception {
       this.executor = executor;
-      files = new ArrayList<>();
       dbDriver = JDBCUtils.getDBFileDriver(dataSource, tableName, sqlProvider);
    }
 
@@ -61,7 +60,6 @@ public class JDBCSequentialFileFactory implements SequentialFileFactory, ActiveM
                                     final SQLProvider sqlProvider,
                                     Executor executor) throws Exception {
       this.executor = executor;
-      files = new ArrayList<>();
       dbDriver = JDBCUtils.getDBFileDriver(className, connectionUrl, sqlProvider);
    }
 

artemis-jdbc-store/src/main/java/org/apache/activemq/artemis/jdbc/store/journal/JDBCJournalImpl.java

@@ -83,7 +83,7 @@ public class JDBCJournalImpl extends AbstractJDBCDriver implements Journal {
    private Map<Long, TransactionHolder> transactions = new ConcurrentHashMap<>();
 
    // Sequence ID for journal records
-   private AtomicLong seq = new AtomicLong(0);
+   private final AtomicLong seq = new AtomicLong(0);
 
    public JDBCJournalImpl(DataSource dataSource, SQLProvider provider, String tableName, ScheduledExecutorService scheduledExecutorService, Executor completeExecutor) {
       super(dataSource, provider);

artemis-jms-client/src/main/java/org/apache/activemq/artemis/jms/client/ThreadAwareContext.java

@@ -39,7 +39,7 @@ public class ThreadAwareContext {
     * Use a set because JMSContext can create more than one JMSConsumer
     * to receive asynchronously from different destinations.
     */
-   private Set<Long> messageListenerThreads = new ConcurrentHashSet<>();
+   private final Set<Long> messageListenerThreads = new ConcurrentHashSet<>();
 
    /**
     * Sets current thread to the context

artemis-protocols/artemis-openwire-protocol/src/main/java/org/apache/activemq/artemis/core/protocol/openwire/OpenWireConnection.java

@@ -144,13 +144,13 @@ public class OpenWireConnection extends AbstractRemotingConnection implements Se
    private final AtomicBoolean asyncException = new AtomicBoolean(false);
 
    // Clebert: Artemis session has meta-data support, perhaps we could reuse it here
-   private Map<String, SessionId> sessionIdMap = new ConcurrentHashMap<>();
+   private final Map<String, SessionId> sessionIdMap = new ConcurrentHashMap<>();
 
    private final Map<ConsumerId, AMQConsumerBrokerExchange> consumerExchanges = new ConcurrentHashMap<>();
    private final Map<ProducerId, AMQProducerBrokerExchange> producerExchanges = new ConcurrentHashMap<>();
 
    // Clebert TODO: Artemis already stores the Session. Why do we need a different one here
-   private Map<SessionId, AMQSession> sessions = new ConcurrentHashMap<>();
+   private final Map<SessionId, AMQSession> sessions = new ConcurrentHashMap<>();
 
    private ConnectionState state;
 
@@ -160,7 +160,7 @@ public class OpenWireConnection extends AbstractRemotingConnection implements Se
     * But always without any association with Sessions.
     * This collection will hold nonXA transactions. Hopefully while they are in transit only.
     */
-   private Map<TransactionId, Transaction> txMap = new ConcurrentHashMap<>();
+   private final Map<TransactionId, Transaction> txMap = new ConcurrentHashMap<>();
 
    private volatile AMQSession advisorySession;
 

artemis-ra/src/main/java/org/apache/activemq/artemis/ra/inflow/ActiveMQActivation.java

@@ -115,9 +115,9 @@ public class ActiveMQActivation {
 
    private ActiveMQConnectionFactory factory;
 
-   private List<String> nodes = Collections.synchronizedList(new ArrayList<String>());
+   private final List<String> nodes = Collections.synchronizedList(new ArrayList<String>());
 
-   private Map<String, Long> removedNodes = new ConcurrentHashMap<>();
+   private final Map<String, Long> removedNodes = new ConcurrentHashMap<>();
 
    private boolean lastReceived = false;
 

artemis-rest/src/main/java/org/apache/activemq/artemis/rest/queue/QueueDestinationsResource.java

@@ -45,8 +45,8 @@ import org.w3c.dom.Document;
 @Path(Constants.PATH_FOR_QUEUES)
 public class QueueDestinationsResource {
 
-   private Map<String, QueueResource> queues = new ConcurrentHashMap<>();
+   private final Map<String, QueueResource> queues = new ConcurrentHashMap<>();
-   private QueueServiceManager manager;
+   private final QueueServiceManager manager;
 
    public QueueDestinationsResource(QueueServiceManager manager) {
       this.manager = manager;

artemis-rest/src/main/java/org/apache/activemq/artemis/rest/topic/TopicDestinationsResource.java

@@ -46,8 +46,8 @@ import org.w3c.dom.Document;
 @Path("/topics")
 public class TopicDestinationsResource {
 
-   private Map<String, TopicResource> topics = new ConcurrentHashMap<>();
+   private final Map<String, TopicResource> topics = new ConcurrentHashMap<>();
-   private TopicServiceManager manager;
+   private final TopicServiceManager manager;
 
    public TopicDestinationsResource(TopicServiceManager manager) {
       this.manager = manager;

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/cluster/ClusterController.java

@@ -69,7 +69,7 @@ public class ClusterController implements ActiveMQComponent {
 
    private final ActiveMQServer server;
 
-   private Map<SimpleString, ServerLocatorInternal> locators = new HashMap<>();
+   private final Map<SimpleString, ServerLocatorInternal> locators = new HashMap<>();
 
    private SimpleString defaultClusterConnectionName;
 
@@ -394,7 +394,7 @@ public class ClusterController implements ActiveMQComponent {
     */
    private final class ConnectRunnable implements Runnable {
 
-      private ServerLocatorInternal serverLocator;
+      private final ServerLocatorInternal serverLocator;
 
       private ConnectRunnable(ServerLocatorInternal serverLocator) {
          this.serverLocator = serverLocator;

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/cluster/ha/ColocatedHAManager.java

@@ -38,7 +38,7 @@ public class ColocatedHAManager implements HAManager {
 
    private final ActiveMQServer server;
 
-   private Map<String, ActiveMQServer> backupServers = new HashMap<>();
+   private final Map<String, ActiveMQServer> backupServers = new HashMap<>();
 
    private boolean started;
 

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/cluster/qourum/QuorumManager.java

@@ -46,7 +46,7 @@ public final class QuorumManager implements ClusterTopologyListener, ActiveMQCom
    /**
     * all the current registered {@link org.apache.activemq.artemis.core.server.cluster.qourum.Quorum}'s
     */
-   private Map<String, Quorum> quorums = new HashMap<>();
+   private final Map<String, Quorum> quorums = new HashMap<>();
 
    /**
     * any currently running runnables.
@@ -253,7 +253,7 @@ public final class QuorumManager implements ClusterTopologyListener, ActiveMQCom
 
    private final class VoteRunnableHolder {
 
-      private QuorumVote quorumVote;
+      private final QuorumVote quorumVote;
       private final List<VoteRunnable> runnables;
       private int size;
 

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/group/impl/LocalGroupingHandler.java

@@ -80,7 +80,7 @@ public final class LocalGroupingHandler extends GroupHandlingAbstract {
 
    private ScheduledFuture reaperFuture;
 
-   private long reaperPeriod;
+   private final long reaperPeriod;
 
    public LocalGroupingHandler(final ExecutorFactory executorFactory,
                                final ScheduledExecutorService scheduledExecutor,

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ActiveMQServerImpl.java

@@ -293,7 +293,7 @@ public class ActiveMQServerImpl implements ActiveMQServer {
 
    private Activation activation;
 
-   private Map<String, Object> activationParams = new HashMap<>();
+   private final Map<String, Object> activationParams = new HashMap<>();
 
    private final ShutdownOnCriticalErrorListener shutdownOnCriticalIO = new ShutdownOnCriticalErrorListener();
 
@@ -306,7 +306,7 @@ public class ActiveMQServerImpl implements ActiveMQServer {
 
    private boolean scheduledPoolSupplied = false;
 
-   private ServiceRegistry serviceRegistry;
+   private final ServiceRegistry serviceRegistry;
 
    private Date startDate;
 

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/QueueImpl.java

@@ -227,9 +227,9 @@ public class QueueImpl implements Queue {
 
    private final ReusableLatch deliveriesInTransit = new ReusableLatch(0);
 
-   private AtomicLong queueRateCheckTime = new AtomicLong(System.currentTimeMillis());
+   private final AtomicLong queueRateCheckTime = new AtomicLong(System.currentTimeMillis());
 
-   private AtomicLong messagesAddedSnapshot = new AtomicLong(0);
+   private final AtomicLong messagesAddedSnapshot = new AtomicLong(0);
 
    private ScheduledFuture slowConsumerReaperFuture;
 
@@ -3005,9 +3005,9 @@ public class QueueImpl implements Queue {
 
    private final class SlowConsumerReaperRunnable implements Runnable {
 
-      private SlowConsumerPolicy policy;
+      private final SlowConsumerPolicy policy;
-      private float threshold;
+      private final float threshold;
-      private long checkPeriod;
+      private final long checkPeriod;
 
       private SlowConsumerReaperRunnable(long checkPeriod, float threshold, SlowConsumerPolicy policy) {
          this.checkPeriod = checkPeriod;

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/reload/ReloadManagerImpl.java

@@ -36,7 +36,7 @@ public class ReloadManagerImpl extends ActiveMQScheduledComponent implements Rel
 
    private volatile Runnable tick;
 
-   private Map<URL, ReloadRegistry> registry = new HashMap<>();
+   private final Map<URL, ReloadRegistry> registry = new HashMap<>();
 
    public ReloadManagerImpl(ScheduledExecutorService scheduledExecutorService, Executor executor, long checkPeriod) {
       super(scheduledExecutorService, executor, checkPeriod, TimeUnit.MILLISECONDS, false);

artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/security/jaas/CertificateLoginModule.java

@@ -46,7 +46,7 @@ public abstract class CertificateLoginModule extends PropertiesLoader implements
 
    private X509Certificate[] certificates;
    private String username;
-   private Set<Principal> principals = new HashSet<>();
+   private final Set<Principal> principals = new HashSet<>();
 
    /**
     * Overriding to allow for proper initialization. Standard JAAS.

artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/security/jaas/GuestLoginModule.java

@@ -50,7 +50,7 @@ public class GuestLoginModule implements LoginModule {
    private Subject subject;
    private boolean debug;
    private boolean credentialsInvalidate;
-   private Set<Principal> principals = new HashSet<>();
+   private final Set<Principal> principals = new HashSet<>();
    private CallbackHandler callbackHandler;
    private boolean loginSucceeded;
 

artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/security/jaas/InVMLoginModule.java

@@ -44,7 +44,7 @@ public class InVMLoginModule implements LoginModule {
    private SecurityConfiguration configuration;
    private Subject subject;
    private String user;
-   private Set<Principal> principals = new HashSet<>();
+   private final Set<Principal> principals = new HashSet<>();
    private CallbackHandler callbackHandler;
    private boolean loginSucceeded;
 

artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/security/jaas/LDAPLoginModule.java

@@ -82,7 +82,7 @@ public class LDAPLoginModule implements LoginModule {
    private CallbackHandler handler;
    private LDAPLoginProperty[] config;
    private String username;
-   private Set<RolePrincipal> groups = new HashSet<>();
+   private final Set<RolePrincipal> groups = new HashSet<>();
 
    @Override
    public void initialize(Subject subject, CallbackHandler callbackHandler, Map<String, ?> sharedState, Map<String, ?> options) {

tests/activemq5-unit-tests/src/test/java/org/apache/activemq/transport/failover/FailoverPriorityTest.java

@@ -48,9 +48,9 @@ public class FailoverPriorityTest extends OpenwireArtemisBaseTest {
    private final HashMap<Integer, String> urls = new HashMap<>();
 
    private final List<ActiveMQConnection> connections = new ArrayList<>();
-   private EmbeddedJMS[] servers = new EmbeddedJMS[3];
+   private final EmbeddedJMS[] servers = new EmbeddedJMS[3];
    private String clientUrl;
-   private Map<String, String> params = new HashMap<>();
+   private final Map<String, String> params = new HashMap<>();
 
    @Before
    public void setUp() throws Exception {

tests/activemq5-unit-tests/src/test/java/org/apache/activemq/usecases/QueueDuplicatesTest.java

@@ -118,7 +118,7 @@ public class QueueDuplicatesTest extends TestCase {
 
    private class SendingThread extends Thread {
 
-      private String subject;
+      private final String subject;
 
       SendingThread(String brokerUrl, String subject) {
          this.subject = subject;
@@ -149,7 +149,7 @@ public class QueueDuplicatesTest extends TestCase {
 
    private static class SimpleConsumer implements MessageListener {
 
-      private Map<String, Message> msgs = new HashMap<>();
+      private final Map<String, Message> msgs = new HashMap<>();
 
       @Override
       public void onMessage(Message message) {