Merge branch '1.3.x'

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -17,11 +17,13 @@
 package org.springframework.boot.devtools.restart;
 
 import java.lang.Thread.UncaughtExceptionHandler;
+import java.util.Arrays;
 
 /**
  * {@link UncaughtExceptionHandler} decorator that allows a thread to exit silently.
  *
  * @author Phillip Webb
+ * @author Andy Wilkinson
  */
 class SilentExitExceptionHandler implements UncaughtExceptionHandler {
 
@@ -34,6 +36,9 @@ class SilentExitExceptionHandler implements UncaughtExceptionHandler {
 	@Override
 	public void uncaughtException(Thread thread, Throwable exception) {
 		if (exception instanceof SilentExitException) {
+			if (jvmWillExit(thread)) {
+				preventNonZeroExitCode();
+			}
 			return;
 		}
 		if (this.delegate != null) {
@@ -53,6 +58,41 @@ class SilentExitExceptionHandler implements UncaughtExceptionHandler {
 		throw new SilentExitException();
 	}
 
+	private boolean jvmWillExit(Thread exceptionThread) {
+		for (Thread thread : getAllThreads()) {
+			if (thread != exceptionThread && thread.isAlive() && !thread.isDaemon()) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	protected void preventNonZeroExitCode() {
+		System.exit(0);
+	}
+
+	protected Thread[] getAllThreads() {
+		ThreadGroup rootThreadGroup = getRootThreadGroup();
+		int size = 32;
+		int threadCount;
+		Thread[] threads;
+		do {
+			size *= 2;
+			threads = new Thread[size];
+			threadCount = rootThreadGroup.enumerate(threads);
+		}
+		while (threadCount == threads.length);
+		return Arrays.copyOf(threads, threadCount);
+	}
+
+	private ThreadGroup getRootThreadGroup() {
+		ThreadGroup candidate = Thread.currentThread().getThreadGroup();
+		while (candidate.getParent() != null) {
+			candidate = candidate.getParent();
+		}
+		return candidate;
+	}
+
 	private static class SilentExitException extends RuntimeException {
 
 	}