INT-4150: Sonar Fixes

"New" issues for previous commit; Sonar reports as "new" issues in
changed files.

spring-integration-mail/src/main/java/org/springframework/integration/mail/AbstractMailReceiver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -556,7 +556,7 @@ public abstract class AbstractMailReceiver extends IntegrationObjectSupport impl
 	}
 
 	@Override
-	public void destroy() throws Exception {
+	public void destroy() {
 		synchronized (this.folderMonitor) {
 			MailTransportUtils.closeFolder(this.folder, this.shouldDeleteMessages);
 			MailTransportUtils.closeService(this.store);

spring-integration-mail/src/main/java/org/springframework/integration/mail/ImapMailReceiver.java

@@ -149,7 +149,7 @@ public class ImapMailReceiver extends AbstractMailReceiver {
 	}
 
 	@Override
-	public void destroy() throws Exception {
+	public void destroy() {
 		super.destroy();
 		if (this.isInternalScheduler) {
 			((ThreadPoolTaskScheduler) this.scheduler).shutdown();

spring-integration-test-support/src/main/java/org/springframework/integration/test/mail/TestMailServer.java

@@ -237,6 +237,11 @@ public class TestMailServer {
 
 		class ImapHandler extends MailHandler {
 
+			/**
+			 * Time to wait while IDLE before returning a result.
+			 */
+			private static final int IDLE_WAIT_TIME = 1000;
+
 			ImapHandler(Socket socket) {
 				super(socket);
 			}
@@ -348,7 +353,7 @@ public class TestMailServer {
 							idleTag = tag;
 							if (!idled) {
 								try {
-									Thread.sleep(1000);
+									Thread.sleep(IDLE_WAIT_TIME);
 									write("* 2 EXISTS");
 									seen = false;
 								}
@@ -392,9 +397,9 @@ public class TestMailServer {
 
 		private final ExecutorService exec = Executors.newCachedThreadPool();
 
-		protected final Set<String> assertions = new HashSet<>();
+		protected final Set<String> assertions = new HashSet<>(); // NOSONAR protected
 
-		protected final List<String> messages = new ArrayList<>();
+		protected final List<String> messages = new ArrayList<>(); // NOSONAR protected
 
 		private volatile boolean listening;
 
@@ -461,13 +466,13 @@ public class TestMailServer {
 					+ "Subject: Test Email\r\n"
 					+ "\r\n" + BODY;
 
-			protected final Socket socket;
+			protected final Socket socket; // NOSONAR protected
 
 			private BufferedWriter writer;
 
-			StringBuilder sb = new StringBuilder();
+			protected StringBuilder sb = new StringBuilder(); // NOSONAR protected
 
-			protected BufferedReader reader;
+			protected BufferedReader reader; // NOSONAR protected
 
 			MailHandler(Socket socket) {
 				this.socket = socket;