Fix: handle null event, misc IDE warnings

Signed-off-by: Evgeny Malygin <emalygin@bloomberg.net>

Author: 678098

README.md

@@ -66,19 +66,27 @@ $ mvn clean -Dmaven.test.skip=true -Dspotbugs.skip=true install
 
 ### Build and Run `bmq-examples` Producer Example
 
+Prerequisites:
+- BlazingMQ backend is built and is available.
+- `bmq-sdk` JAR is installed locally.
+
+Java SDK producers/consumers can be tested with the local BlazingMQ broker.
+For Linux build, first start the local broker:
+```sh
+cd $BLAZINGMQ_DIR/build/Linux/src/applications/bmqbrkr
+./run
+```
+
+Secondly, start sample producer, that will connect to the local broker, open a queue, post messages and exits:
 ```sh
 $ cd bmq-examples
 $ mvn clean compile
-$ mvn exec:java -Dexec.mainClass="com.bloomberg.bmq.examples.Producer"
+$ mvn exec:java -Dexec.mainClass="com.bloomberg.bmq.examples.SimpleProducer"
 ```
 
-Above command expects that `bmq-sdk` JAR is installed locally.  Also note that
-BlazingMQ backend must be running for producer/consumer examples to run
-successfully.
-
 ### Building BlazingMQ Backend
 
-Detailed instructions to build BlazingMQ backend (BlazingMQ message brokers,
+Detailed instructions on how to build BlazingMQ backend (BlazingMQ message brokers,
 etc) can be found [here](https://www.github.com/bloomberg/blazingmq).
 
 ### Supported JDKs
@@ -166,7 +174,7 @@ in the project, please contact us at opensource@bloomberg.net.
 ## Security Vulnerability Reporting
 
 If you believe you have identified a security vulnerability in this project,
-please send an email to the project team at opensource@bloomberg.net, detailing
+please email the project team at opensource@bloomberg.net, detailing
 the suspected issue and any methods you've found to reproduce it.
 
 Please do NOT open an issue in the GitHub repository, as we'd prefer to keep

bmq-sdk/src/main/java/com/bloomberg/bmq/SubscriptionExpression.java

@@ -42,7 +42,7 @@ public SubscriptionExpression(String expression) {
         Argument.expectNonNull(expression, "expression");
         this.expression = Optional.of(expression);
         this.version =
-                Optional.of((expression.length() > 0) ? Version.e_VERSION_1 : Version.e_UNDEFINED);
+                Optional.of((!expression.isEmpty()) ? Version.e_VERSION_1 : Version.e_UNDEFINED);
     }
 
     public SubscriptionExpression() {

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/BrokerSession.java

@@ -598,7 +598,7 @@ private CompletableFuture<Void> execQueueManagerCleanUp() {
                                         .collect(Collectors.toList());
                         if (!activeStrategies.isEmpty()) {
                             // If given list is not empty, then cancel all unfinished sequences
-                            // and set up clean up action as a continuation executed in scheduler.
+                            // and set up cleanup action as a continuation executed in scheduler.
                             activeStrategies.forEach(QueueControlStrategy::cancelOnStop);
                             activeStrategies.stream()
                                     .map(QueueControlStrategy::getResultFuture)

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/ProtocolEventTcpReader.java

@@ -79,7 +79,7 @@ public void read(
                 data.length,
                 completionStatus.numNeeded());
         try {
-            EventHeader eventHeader = null;
+            EventHeader eventHeader;
             for (ByteBuffer restData : data) {
                 boolean done = false;
                 while (!done) {

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/TcpBrokerConnection.java

@@ -437,6 +437,11 @@ private boolean validateBrokerResponse(BrokerResponse resp) {
     private class EventHandler implements ProtocolEventTcpReader.EventHandler {
 
         public void handleEvent(EventType eventType, ByteBuffer[] bbuf) {
+            if (eventType == null) {
+                logger.warn("Received null event type with buffer size: {}, skipping", bbuf.length);
+                return;
+            }
+
             logger.debug("Handle EventImpl {} with size: {}", eventType, bbuf.length);
             EventImpl reportedEvent;
             switch (eventType) {

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/events/BrokerSessionEvent.java

@@ -52,7 +52,7 @@ public void dispatch(BrokerSessionEventHandler handler, BrokerSessionEvent event
 
     private static final int TYPE_ID = UniqId.getNumber();
 
-    public final void dispatch(BrokerSessionEventHandler handler) {
+    public void dispatch(BrokerSessionEventHandler handler) {
         getEventType().dispatch(handler, this);
     }
 

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/events/QueueControlEvent.java

@@ -78,7 +78,7 @@ public final void dispatch(QueueControlEventHandler handler) {
         getEventType().dispatch(handler, this);
     }
 
-    private QueueHandle queue;
+    private final QueueHandle queue;
 
     private QueueControlEvent(
             Type queueEventType, GenericCode result, String errorDescription, QueueHandle queue) {

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/infr/net/NettyTcpConnection.java

@@ -80,7 +80,7 @@ public final class NettyTcpConnection extends ChannelInboundHandlerAdapter
      * <p>Other goals are to inject server responses and as well as to keep the threading model same
      * in the test code. The best candidate is {@link io.netty.channel.embedded.EmbeddedChannel}
      * class that lets us inject responses. The main problem with given class is the fact that it is
-     * "threadless" and unfortunately does not allow us to inject custom eventloop. But we can
+     * "threadless" and unfortunately does not allow us to inject custom event loop. But we can
      * inject it in our channel adapter and execute every embedded channel routine in IO thread. So,
      * it helps to achieve thread safety for plain embedded channel class and at the same time,
      * reproduce the threading model for tested class.
@@ -200,7 +200,7 @@ private enum ChannelState {
     private boolean wasOnceConnected;
     private int numRemainingInitialTries;
     private ConnectionOptions options;
-    private NetResolver hostResolver;
+    private final NetResolver hostResolver;
     private ReadCompletionStatus readBytesStatus;
     private EventLoopGroup eventLoop;
     private Bootstrap bootstrap;
@@ -210,7 +210,7 @@ private enum ChannelState {
     private DisconnectCallback disconnectCallback;
     private ChannelStatusHandler channelStatusHandler;
     private Semaphore channelWaterMarkSema;
-    private ClientChannelAdapter clientChannelAdapter;
+    private final ClientChannelAdapter clientChannelAdapter;
     private final long lingerTimeout;
 
     static {
@@ -476,7 +476,7 @@ public int disconnect(DisconnectCallback disconnectCb) {
             disconnectCallback = disconnectCb;
 
             // If the callback is not null, then we are going to do full
-            // disconnect procedure. Otherwise we just drop the channel and
+            // disconnect procedure. Otherwise, we just drop the channel and
             // schedule reconnecting (see 'channelCloseFutureComplete' method).
             if (disconnectCb != null) {
                 state = ChannelState.DISCONNECTING;

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/infr/proto/EventType.java

@@ -23,7 +23,7 @@ public enum EventType {
     PUSH(4),
     ACK(5);
 
-    private int id;
+    private final int id;
 
     EventType(int id) {
         this.id = id;

bmq-sdk/src/main/java/com/bloomberg/bmq/impl/infr/scm/VersionUtil.java

@@ -72,7 +72,7 @@ public static int getSdkVersion() {
         logger.info("BlazingMQ SDK Jar ImplementationVersion: [{}]", implVersion);
 
         if (implVersion == null) {
-            // When loaded outside of a JAR, just return a default value of
+            // When loaded outside a JAR, just return a default value of
             // 999999 , which is what we return in C++ when program is built
             // from the master instead of using 'libbmq'.
             return DEFAULT_VERSION;