Sonar fixes

- printStackTrace in test mail server
- Illegal throws
- Large anon. classes

* - indexOf char
- stored external object

* - ignored exceptional return values

* - checkstyle

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

@@ -32,6 +32,9 @@ import java.util.concurrent.Executors;
 
 import javax.net.ServerSocketFactory;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import org.springframework.util.Base64Utils;
 
 /**
@@ -145,7 +148,7 @@ public final class TestMailServer {
 					messages.add(sb.toString());
 				}
 				catch (IOException e) {
-					e.printStackTrace();
+					LOGGER.error(IO_EXCEPTION, e);
 				}
 			}
 
@@ -205,7 +208,7 @@ public final class TestMailServer {
 					}
 				}
 				catch (IOException e) {
-					e.printStackTrace();
+					LOGGER.error(IO_EXCEPTION, e);
 				}
 			}
 
@@ -256,7 +259,7 @@ public final class TestMailServer {
 						if (line == null) {
 							break;
 						}
-						String tag = line.substring(0, line.indexOf(" ") + 1);
+						String tag = line.substring(0, line.indexOf(' ') + 1);
 						if (line.endsWith("CAPABILITY")) {
 							write("* CAPABILITY IDLE IMAP4rev1");
 							write(tag + "OK CAPABILITY completed");
@@ -357,7 +360,7 @@ public final class TestMailServer {
 									write("* 2 EXISTS");
 									seen = false;
 								}
-								catch (InterruptedException e) {
+								catch (@SuppressWarnings("unused") InterruptedException e) {
 									Thread.currentThread().interrupt();
 								}
 							}
@@ -373,7 +376,7 @@ public final class TestMailServer {
 					}
 				}
 				catch (IOException e) {
-					e.printStackTrace();
+					LOGGER.error(IO_EXCEPTION, e);
 				}
 			}
 
@@ -393,6 +396,10 @@ public final class TestMailServer {
 
 	public abstract static class MailServer implements Runnable {
 
+		protected final Log LOGGER = LogFactory.getLog(getClass()); // NOSONAR
+
+		protected static final String IO_EXCEPTION = "IOException"; // NOSONAR
+
 		private final ServerSocket serverSocket;
 
 		private final ExecutorService exec = Executors.newCachedThreadPool();
@@ -437,7 +444,7 @@ public final class TestMailServer {
 					exec.execute(mailHandler(socket));
 				}
 			}
-			catch (IOException e) {
+			catch (@SuppressWarnings("unused") IOException e) {
 				this.listening = false;
 			}
 		}
@@ -449,7 +456,7 @@ public final class TestMailServer {
 				this.serverSocket.close();
 			}
 			catch (IOException e) {
-				e.printStackTrace();
+				LOGGER.error(IO_EXCEPTION, e);
 			}
 			this.exec.shutdownNow();
 		}
@@ -485,7 +492,7 @@ public final class TestMailServer {
 					this.writer = new BufferedWriter(new OutputStreamWriter(this.socket.getOutputStream()));
 				}
 				catch (IOException e) {
-					e.printStackTrace();
+					LOGGER.error(IO_EXCEPTION, e);
 				}
 				doRun();
 			}

spring-integration-test-support/src/main/java/org/springframework/integration/test/rule/Log4j2LevelAdjuster.java

@@ -77,7 +77,7 @@ public final class Log4j2LevelAdjuster implements MethodRule {
 
 	@Override
 	public Statement apply(final Statement base, final FrameworkMethod method, Object target) {
-		return new Statement() {
+		class AdjustingStatement extends Statement {
 
 			@Override
 			public void evaluate() throws Throwable {
@@ -152,19 +152,19 @@ public final class Log4j2LevelAdjuster implements MethodRule {
 					ctx.updateLoggers();
 				}
 			}
-
-		};
+		}
+		return new AdjustingStatement();
 	}
 
 	/**
 	 * Specify the classes for logging level adjusting configured before.
 	 * A new copy Log4j2LevelAdjuster instance is produced by this method.
 	 * The provided classes parameter overrides existing value in the {@link #classes}.
-	 * @param classes the classes to use for logging level adjusting
+	 * @param clazzes the classes to use for logging level adjusting
 	 * @return a Log4j2LevelAdjuster copy with the provided classes
 	 */
-	public Log4j2LevelAdjuster classes(Class<?>... classes) {
-		return classes(false, classes);
+	public Log4j2LevelAdjuster classes(Class<?>... clazzes) {
+		return classes(false, clazzes);
 	}
 
 	/**
@@ -172,13 +172,13 @@ public final class Log4j2LevelAdjuster implements MethodRule {
 	 * A new copy Log4j2LevelAdjuster instance is produced by this method.
 	 * The provided classes parameter can be merged with existing value in the {@link #classes}.
 	 * @param merge to merge or not with previously configured {@link #classes}
-	 * @param classes the classes to use for logging level adjusting
+	 * @param classesToAdjust the classes to use for logging level adjusting
 	 * @return a Log4j2LevelAdjuster copy with the provided classes
 	 * @since 5.0.2
 	 */
-	public Log4j2LevelAdjuster classes(boolean merge, Class<?>... classes) {
+	public Log4j2LevelAdjuster classes(boolean merge, Class<?>... classesToAdjust) {
 		return new Log4j2LevelAdjuster(this.level,
-				merge ? Stream.of(this.classes, classes).flatMap(Stream::of).toArray(Class<?>[]::new) : classes,
+				merge ? Stream.of(this.classes, classesToAdjust).flatMap(Stream::of).toArray(Class<?>[]::new) : classesToAdjust,
 				this.categories);
 	}
 
@@ -186,11 +186,11 @@ public final class Log4j2LevelAdjuster implements MethodRule {
 	 * Specify the categories for logging level adjusting configured before.
 	 * A new copy Log4j2LevelAdjuster instance is produced by this method.
 	 * The provided categories parameter overrides existing value in the {@link #categories}.
-	 * @param categories the categories to use for logging level adjusting
+	 * @param categoriesToAdjust the categories to use for logging level adjusting
 	 * @return a Log4j2LevelAdjuster copy with the provided categories
 	 */
-	public Log4j2LevelAdjuster categories(String... categories) {
-		return categories(false, categories);
+	public Log4j2LevelAdjuster categories(String... categoriesToAdjust) {
+		return categories(false, categoriesToAdjust);
 	}
 
 	/**