Remove duplicate words

Closes gh-1039

spring-messaging/src/main/java/org/springframework/messaging/simp/config/TaskExecutorRegistration.java

@@ -52,7 +52,7 @@ public class TaskExecutorRegistration {
 	 * in {@link java.util.concurrent.ThreadPoolExecutor ThreadPoolExecutor}. When
 	 * this strategy is used, the {@link #maxPoolSize(int) maxPoolSize} is ignored.
 	 * <p>By default this is set to twice the value of
-	 * {@link Runtime#availableProcessors()}. In an an application where tasks do not
+	 * {@link Runtime#availableProcessors()}. In an application where tasks do not
 	 * block frequently, the number should be closer to or equal to the number of
 	 * available CPUs/cores.
 	 */

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java

@@ -60,7 +60,7 @@ import org.springframework.util.concurrent.ListenableFutureTask;
  *
  * <p>This class also automatically opens a default "system" TCP connection to the message
  * broker that is used for sending messages that originate from the server application (as
- * opposed to from a client). Such messages are are not associated with any client and
+ * opposed to from a client). Such messages are not associated with any client and
  * therefore do not have a session id header. The "system" connection is effectively
  * shared and cannot be used to receive messages. Several properties are provided to
  * configure the "system" connection including:

spring-messaging/src/main/java/org/springframework/messaging/tcp/TcpConnection.java

@@ -39,14 +39,14 @@ public interface TcpConnection<P> extends Closeable {
 	ListenableFuture<Void> send(Message<P> message);
 
 	/**
-	 * Register a task to invoke after a period of of read inactivity.
+	 * Register a task to invoke after a period of read inactivity.
 	 * @param runnable the task to invoke
 	 * @param duration the amount of inactive time in milliseconds
 	 */
 	void onReadInactivity(Runnable runnable, long duration);
 
 	/**
-	 * Register a task to invoke after a period of of write inactivity.
+	 * Register a task to invoke after a period of write inactivity.
 	 * @param runnable the task to invoke
 	 * @param duration the amount of inactive time in milliseconds
 	 */