How to give name to a callable Thread? [duplicate]

Answer 1

I just had to do what you are asking for -- providing names to my thread groups -- so thanks to Andeas's answer, I created my own ThreadFactory as an inner-class to the class that is going to use it by copying Executors$DefaultThreadFactory, changing 3 lines by adding the parameter "groupname" to the constructor.

    /**
 * A thread factory that names each thread with the provided group name.
 * 

 * Except lines with "elarson modified", copied from code 
 * Executors$DefaultThreadFactory -- Doug Lea, Copyright Oracle, et al.
 */
static class GroupNameThreadFactory implements ThreadFactory {
    private String groupname; /* elarson modified */
    private static final AtomicInteger poolNumber = new AtomicInteger(1);
    private final ThreadGroup group;
    private final AtomicInteger threadNumber = new AtomicInteger(1);
    private final String namePrefix;

    GroupNameThreadFactory(String groupname) {
        this.groupname = groupname; /* elarson modified */
        SecurityManager s = System.getSecurityManager();
        group = (s != null) ? s.getThreadGroup() :
                              Thread.currentThread().getThreadGroup();
        namePrefix = "pool-" +
                       this.groupname + /* elarson modified */
                       poolNumber.getAndIncrement() +
                     "-thread-";
    }

    public Thread newThread(Runnable r) {
        Thread t = new Thread(group, r,
                              namePrefix + threadNumber.getAndIncrement(),
                              0);
        if (t.isDaemon())
            t.setDaemon(false);
        if (t.getPriority() != Thread.NORM_PRIORITY)
            t.setPriority(Thread.NORM_PRIORITY);
        return t;
    }
}

Creating a ThreadPool from it is done as follows.

        ThreadFactory threadfactory = new GroupNameThreadFactory("Monitor");    
    executor = Executors.newFixedThreadPool(NUM_THREADS, threadfactory);

Thanks user381878 for asking the question, and Andreas for the answer.