Naming threads created with the ExecutorService

When profiling applications it sometimes becomes a pain to understand where so many threads come from and what the hell they are doing.

If you’re like me and have a dependency on java.util.concurrent‘s API’s for anything concurrency-related, then you’ve certainly noticed that default thread names aren’t particularly helpful with the aforementioned problem.
Here’s a quick & dirty implementation of a ThreadFactory (based on Executors.DefaultThreadFactory) but with support for your own thread name prefixes.

public class NamedThreadFactory implements ThreadFactory {
 
    // constants -----------------------------------------------------------------
 
    private static final AtomicInteger POOL_NUMBER = new AtomicInteger(1);
 
    // internal vars -------------------------------------------------------------
 
    private final ThreadGroup group;
    private final AtomicInteger threadNumber = new AtomicInteger(1);
    private final String namePrefix;
 
    // constructors --------------------------------------------------------------
 
    public NamedThreadFactory() {
        this("ThreadPool(" + POOL_NUMBER.getAndIncrement() + "-thread-");
    }
 
    public NamedThreadFactory(String namePrefix) {
        SecurityManager s = System.getSecurityManager();
        this.group = (s != null) ? s.getThreadGroup() :
                     Thread.currentThread().getThreadGroup();
        this.namePrefix = namePrefix + "(pool" +
                          POOL_NUMBER.getAndIncrement() + "-thread-";
    }
 
    // ThreadFactory -------------------------------------------------------------
 
    public Thread newThread(Runnable r) {
        Thread t = new Thread(this.group, r, this.namePrefix +
                              this.threadNumber.getAndIncrement() + ")", 0L);
        if (t.isDaemon()) {
            t.setDaemon(false);
        }
        if (t.getPriority() != Thread.NORM_PRIORITY) {
            t.setPriority(Thread.NORM_PRIORITY);
        }
        return t;
    }
}

Tip: If you’re using Spring, you can just use CustomizableThreadFactory and save yourself the trouble.