Update logging listener to use normal stack trace ordering by default

Previously, LoggingApplicationListener used %rEx as the default
exception conversion word. This would result in the nested causes
being logging in reverse order, i.e. the most deeply nested cause
would be logged first.

This commit updates the default to be %wEx and adds a test to verify
the default behaviour.

Closes gh-4247

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -58,7 +58,7 @@ content into your application; rather pick only the properties that you need.
 
 	# LOGGING
 	logging.config= # location of config file (default classpath:logback.xml for logback)
-	logging.exception-conversion-word=%rEx # conversion word used when logging exceptions
+	logging.exception-conversion-word=%wEx # conversion word used when logging exceptions
 	logging.file=myapp.log
 	logging.level.*= # levels for loggers, e.g. "logging.level.org.springframework=DEBUG" (TRACE, DEBUG, INFO, WARN, ERROR, FATAL, OFF)
 	logging.path=/var/log

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

@@ -200,7 +200,8 @@ public class LoggingApplicationListener implements GenericApplicationListener {
 	}
 
 	private void onApplicationPreparedEvent(ApplicationPreparedEvent event) {
-		ConfigurableListableBeanFactory beanFactory = event.getApplicationContext().getBeanFactory();
+		ConfigurableListableBeanFactory beanFactory = event.getApplicationContext()
+				.getBeanFactory();
 		if (!beanFactory.containsBean(LOGGING_SYSTEM_BEAN_NAME)) {
 			beanFactory.registerSingleton(LOGGING_SYSTEM_BEAN_NAME, this.loggingSystem);
 		}
@@ -236,7 +237,7 @@ public class LoggingApplicationListener implements GenericApplicationListener {
 	private String getExceptionConversionWord(ConfigurableEnvironment environment) {
 		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(environment,
 				"logging.");
-		return resolver.getProperty("exception-conversion-word", "%rEx");
+		return resolver.getProperty("exception-conversion-word", "%wEx");
 	}
 
 	private void initializeEarlyLoggingLevel(ConfigurableEnvironment environment) {

spring-boot/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -33,7 +33,7 @@
     "name": "logging.exception-conversion-word",
     "type": "java.lang.String",
     "description": "Conversion word used when logging exceptions.",
-    "defaultValue": "%rEx",
+    "defaultValue": "%wEx",
     "sourceType": "org.springframework.boot.logging.LoggingApplicationListener"
   },
   {

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

@@ -336,15 +336,27 @@ public class LoggingApplicationListenerTests {
 	}
 
 	@Test
-	public void overrideExceptionConversionWord() throws Exception {
-		EnvironmentTestUtils.addEnvironment(this.context,
-				"logging.exceptionConversionWord:%ex");
+	public void defaultExceptionConversionWord() throws Exception {
 		this.initializer.initialize(this.context.getEnvironment(),
 				this.context.getClassLoader());
 		this.outputCapture.expect(containsString("Hello world"));
-		this.outputCapture.expect(not(containsString("???")));
-		this.outputCapture.expect(not(containsString("[junit-")));
-		this.logger.info("Hello world", new RuntimeException("Expected"));
+		this.outputCapture.expect(
+				not(containsString("Wrapped by: java.lang.RuntimeException: Wrapper")));
+		this.logger.info("Hello world",
+				new RuntimeException("Wrapper", new RuntimeException("Expected")));
+	}
+
+	@Test
+	public void overrideExceptionConversionWord() throws Exception {
+		EnvironmentTestUtils.addEnvironment(this.context,
+				"logging.exceptionConversionWord:%rEx");
+		this.initializer.initialize(this.context.getEnvironment(),
+				this.context.getClassLoader());
+		this.outputCapture.expect(containsString("Hello world"));
+		this.outputCapture.expect(
+				containsString("Wrapped by: java.lang.RuntimeException: Wrapper"));
+		this.logger.info("Hello world",
+				new RuntimeException("Wrapper", new RuntimeException("Expected")));
 	}
 
 	@Test