Shut down logging system as part of clean up processing

Previously, when a LoggingSystem was cleaned up the underlying logging
system (LogBack, Log4J, Log4J2, JUL) was not being properly shut down.
LogBack explicitly recommends stopping it cleanly [1]. While the other
logging systems are less explicity about it, they would all appear to
benefit from being stopped.

This commit updates all four LoggingSystems to stop/reset/clean up to
underlying logging system when cleanUp is called.

Closes gh-4026

[1] http://logback.qos.ch/manual/configuration.html#stopContext

spring-boot/src/main/java/org/springframework/boot/logging/java/JavaLoggingSystem.java

@@ -113,4 +113,10 @@ public class JavaLoggingSystem extends AbstractLoggingSystem {
 		logger.setLevel(LEVELS.get(level));
 	}
 
+	@Override
+	public void cleanUp() {
+		super.cleanUp();
+		LogManager.getLogManager().reset();
+	}
+
 }

spring-boot/src/main/java/org/springframework/boot/logging/log4j/Log4JLoggingSystem.java

@@ -115,4 +115,10 @@ public class Log4JLoggingSystem extends Slf4JLoggingSystem {
 		logger.setLevel(LEVELS.get(level));
 	}
 
+	@Override
+	public void cleanUp() {
+		super.cleanUp();
+		LogManager.shutdown();
+	}
+
 }

spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java

@@ -152,6 +152,12 @@ public class Log4J2LoggingSystem extends Slf4JLoggingSystem {
 		loadConfiguration(location, logFile);
 	}
 
+	@Override
+	public void cleanUp() {
+		super.cleanUp();
+		getLoggerContext().stop();
+	}
+
 	protected void loadConfiguration(String location, LogFile logFile) {
 		Assert.notNull(location, "Location must not be null");
 		if (logFile != null) {

spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystem.java

@@ -177,6 +177,7 @@ public class LogbackLoggingSystem extends Slf4JLoggingSystem {
 	public void cleanUp() {
 		super.cleanUp();
 		getLoggerContext().getStatusManager().clear();
+		getLoggerContext().stop();
 	}
 
 	@Override

spring-boot/src/test/java/org/springframework/boot/logging/java/JavaLoggingSystemTests.java

@@ -20,6 +20,9 @@ import java.io.File;
 import java.io.FileFilter;
 import java.io.IOException;
 import java.util.Locale;
+import java.util.logging.Handler;
+import java.util.logging.LogManager;
+import java.util.logging.LogRecord;
 
 import org.apache.commons.logging.impl.Jdk14Logger;
 import org.junit.After;
@@ -34,6 +37,7 @@ import org.springframework.util.StringUtils;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
@@ -160,4 +164,33 @@ public class JavaLoggingSystemTests extends AbstractLoggingSystemTests {
 				equalTo(1));
 	}
 
+	@Test
+	public void cleanUpResetsLogManager() throws Exception {
+		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(null, null, null);
+		this.logger.getLogger().addHandler(new NoOpHandler());
+		assertThat(this.logger.getLogger().getHandlers().length, is(equalTo(1)));
+		LogManager.getLogManager().reset();
+		assertThat(this.logger.getLogger().getHandlers().length, is(equalTo(0)));
+	}
+
+	private static final class NoOpHandler extends Handler {
+
+		@Override
+		public void publish(LogRecord record) {
+
+		}
+
+		@Override
+		public void flush() {
+
+		}
+
+		@Override
+		public void close() throws SecurityException {
+
+		}
+
+	}
+
 }

spring-boot/src/test/java/org/springframework/boot/logging/log4j/Log4JLoggingSystemTests.java

@@ -139,6 +139,17 @@ public class Log4JLoggingSystemTests extends AbstractLoggingSystemTests {
 		assertFalse(bridgeHandlerInstalled());
 	}
 
+	@Test
+	public void cleanUpStopsLogManager() {
+		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(null, null, null);
+		assertTrue(org.apache.log4j.LogManager.getLoggerRepository().getRootLogger()
+				.getAllAppenders().hasMoreElements());
+		this.loggingSystem.cleanUp();
+		assertFalse(org.apache.log4j.LogManager.getLoggerRepository().getRootLogger()
+				.getAllAppenders().hasMoreElements());
+	}
+
 	private boolean bridgeHandlerInstalled() {
 		java.util.logging.Logger rootLogger = LogManager.getLogManager().getLogger("");
 		Handler[] handlers = rootLogger.getHandlers();

spring-boot/src/test/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystemTests.java

@@ -24,6 +24,7 @@ import java.util.List;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.FileConfigurationMonitor;
 import org.hamcrest.Matcher;
@@ -238,6 +239,17 @@ public class Log4J2LoggingSystemTests extends AbstractLoggingSystemTests {
 		}
 	}
 
+	@Test
+	public void cleanupStopsContext() throws Exception {
+		this.loggingSystem.beforeInitialize();
+		this.logger.info("Hidden");
+		this.loggingSystem.initialize(null, null, null);
+		LoggerContext context = (LoggerContext) LogManager.getContext(false);
+		assertFalse(context.isStopped());
+		this.loggingSystem.cleanUp();
+		assertTrue(context.isStopped());
+	}
+
 	private static class TestLog4J2LoggingSystem extends Log4J2LoggingSystem {
 
 		private List<String> availableClasses = new ArrayList<String>();
@@ -247,8 +259,7 @@ public class Log4J2LoggingSystemTests extends AbstractLoggingSystemTests {
 		}
 
 		public Configuration getConfiguration() {
-			return ((org.apache.logging.log4j.core.LoggerContext) LogManager
-					.getContext(false)).getConfiguration();
+			return ((LoggerContext) LogManager.getContext(false)).getConfiguration();
 		}
 
 		@Override

spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java

@@ -51,6 +51,7 @@ import static org.hamcrest.Matchers.not;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
@@ -121,6 +122,7 @@ public class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 	@Test
 	public void testBasicConfigLocation() throws Exception {
 		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(this.initializationContext, null, null);
 		ILoggerFactory factory = StaticLoggerBinder.getSingleton().getLoggerFactory();
 		LoggerContext context = (LoggerContext) factory;
 		Logger root = context.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
@@ -305,6 +307,19 @@ public class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 		}
 	}
 
+	@Test
+	public void cleanUpStopsContext() throws Exception {
+		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(this.initializationContext, null, null);
+		ILoggerFactory factory = StaticLoggerBinder.getSingleton().getLoggerFactory();
+		LoggerContext context = (LoggerContext) factory;
+		Logger root = context.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
+		assertNotNull(root.getAppender("CONSOLE"));
+
+		this.loggingSystem.cleanUp();
+		assertNull(root.getAppender("CONSOLE"));
+	}
+
 	private String getLineWithText(File file, String outputSearch) throws Exception {
 		return getLineWithText(FileCopyUtils.copyToString(new FileReader(file)),
 				outputSearch);