Checkstyle - Phase I - Unused Imports

I copied the checkstyle config from spring-boot and commented
out most of the rules.

Over time, we should uncomment each rule and fix violations.

spring-integration-jdbc/src/test/java/org/springframework/integration/jdbc/AggregatorIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2014-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@
 package org.springframework.integration.jdbc;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 import java.util.HashMap;
@@ -79,6 +78,7 @@ public class AggregatorIntegrationTests {
 	@SuppressWarnings("unused")
 	private static class ExceptionMessageHandler implements MessageHandler {
 
+		@Override
 		public void handleMessage(Message<?> message) throws MessagingException {
 			TransactionSynchronizationManager.registerSynchronization(new RollbackTxSync());
 			throw new RuntimeException("intentional");

spring-integration-jdbc/src/test/java/org/springframework/integration/jdbc/StoredProcOutboundGatewayWithSpelIntegrationTests.java

@@ -40,7 +40,6 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.integration.annotation.ServiceActivator;
-import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.jdbc.config.JdbcTypesEnum;
 import org.springframework.integration.jdbc.storedproc.User;
 import org.springframework.integration.support.MessageBuilder;