code: public static Collection<Thread> findThreadsByName(final String threadName, final ThreadGroup threadGroup) {
          return findThreads(threadGroup, false, new NamePredicate(threadName));
      }
docs: Return active threads with the specified name if they belong to a specified thread group.
  
  @param threadName The thread name
  @param threadGroup The thread group
  @return The threads which belongs to a thread group and the thread's name match the specified name,
  An empty collection is returned if no such thread exists. The collection returned is always unmodifiable.
  @throws IllegalArgumentException if the specified thread name or group is null
  @throws  SecurityException
  if the current thread cannot access the system thread group
  
  @throws  SecurityException  if the current thread cannot modify
  thread groups from this thread's thread group up to the system thread group