Java tutorial
//package com.java2s; import java.util.Arrays; import java.util.Collections; import java.util.List; public class Main { public static List<Thread> getGroupThreads(ThreadGroup threadGroup) { if (threadGroup == null) { return Collections.emptyList(); } Thread[] threadArray = new Thread[threadGroup.activeCount() * 2]; threadGroup.enumerate(threadArray); return Arrays.asList(threadArray); } }