import jdk.testlibrary.TestThread; //导入依赖的package包/类
private String waitOnTool(String tool, TestThread thread) throws Throwable {
    while (true) {
        String pid = getToolPid(tool);

        if (pid != null) {
            System.out.println(tool + " pid: " + pid);
            return pid;
        }

        Throwable t = thread.getUncaught();
        if (t != null) {
            if (t.getMessage().contains(
                    "java.rmi.server.ExportException: Port already in use")) {
                System.out.println("Port already in use. Trying to restart with a new one...");
                Thread.sleep(100);
                return null;
            } else {
                // Something unexpected has happened
                throw new Throwable(t);
            }
        }

        System.out.println("Waiting until " + tool + " is running...");
        Thread.sleep(100);
    }
}