打印堆栈

public class Trace{
public static void main(String[] args){
Thread[] list = Trace.findAllThreads();
for(Thread thread: list){
StackTraceElement[] trace = thread.getStackTrace();
for(StackTraceElement tra:trace){
System.out.println(tra.toString());
}
}
}

public static Thread[] findAllThreads() {
ThreadGroup group = Thread.currentThread().getThreadGroup();
ThreadGroup topGroup = group;

// 遍历线程组树，获取根线程组
while (group != null) {
topGroup = group;
group = group.getParent();
}
// 激活的线程数加倍
int estimatedSize = topGroup.activeCount() * 2;
Thread[] slackList = new Thread[estimatedSize];
// 获取根线程组的所有线程
int actualSize = topGroup.enumerate(slackList);
// copyintoalistthatistheexactsize
Thread[] list = new Thread[actualSize];
System.arraycopy(slackList, 0, list, 0, actualSize);
return list;
}

}

java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:485)
java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
java.lang.Object.wait(Native Method)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)
java.lang.Thread.getStackTrace(Thread.java:1436)
test.main(test.java:33)