解决方法
如果您是一个应用程序而不必担心SecurityManager限制,并且如果您准备在更新第三方代码时偶尔修改代码,则可以使用ThreadGroup的工具来遍历线程并通过以下方式识别它们：名称或包含它们的线程组.
一旦找到了线程,就可以在它们完成之前监视它们,或者在适当的时候使用Thread.join().
举个例子,这里有一些工作代码转储JVM中的所有线程：
public void printThreads(PrintWriter wtr) {
ThreadGroup root;
totGroups=0;
totThreads=0;
for(root=Thread.currentThread().getThreadGroup(); root.getParent()!=null; root=root.getParent()) {}
wtr.println("Thread Dump:");
printThreadGroup(wtr,root," ");
wtr.println(" -- Total Groups: "+totGroups+",Total Threads: "+totThreads);
}
public void printThreadGroup(PrintWriter wtr,ThreadGroup grp,String pfx) {
try {
Thread[] thds;
ThreadGroup[] grps;
totGroups++;
wtr.println(pfx+"Group: "+grp.getName()+","+(grp.isDaemon()?"Daemon":"Normal")+","+(grp.isDestroyed()?"Destroyed":"Alive")+","+grp.getMaxPriority());
thds=new Thread[grp.activeCount()];
grp.enumerate(thds,false);
Arrays.sort(thds,THREAD_SORTER);
for(int xa=0; xa<thds.length && thds[xa]!=null; xa++,totThreads++) {
Thread thd=thds[xa];
wtr.println(pfx+". - ["+thd.getName()+","+(thd.isDaemon()?"Daemon":"Normal")+","+(thd.isAlive()?"Alive":"Not Started or Dead")+","+thd.getPriority()+"]");
}
grps=new ThreadGroup[grp.activeGroupCount()];
grp.enumerate(grps,false);
Arrays.sort(grps,GROUP_SORTER);
for(int xa=0; xa<grps.length && grps[xa]!=null; xa++) {
printThreadGroup(wtr,grps[xa],(pfx+". "));
grps[xa]=null;
}
}
catch(Throwable thr) {
wtr.println(" Cannot print threads ("+thr+")");
}
}
public void printStacks(PrintWriter wtr) {
wtr.println("Thread Stack Traces:");
try { javaMx.printStacks(wtr); } catch(Throwable thr) { wtr.println(" Cannot print stacks ("+thr+")"); }
wtr.println(" --");
}
