Grouping

• Every Java thread is a member of a ThreadGroup.
• By default, threads are placed in the group of the thread that created them.

public class EnumerateTest {
  public void listCurrentThreads() {
    ThreadGroup currentGroup =
      Thread.currentThread().getThreadGroup();
    int numThreads = currentGroup.activeCount();
    Thread[] listOfThreads = new Thread[numThreads];

    currentGroup.enumerate(listOfThreads);
    for (int i = 0; i < numThreads; i++)
      System.out.println("Thread #" + i + " = " + 
                         listOfThreads[i].getName());
  }
}

• The methods that operate on ThreadGroups are:
  • getMaxPriority and setMaxPriority
  • getDaemon and setDaemon
  • getName
  • getParent and parentOf
  • toString