How to print out all the threads and its current status?

Question

Is there a way to print out all the threads and its id, status using code?

For example, I have 5 threads, and I want to enumerate all of them.

Answer 1

You can do as below.

Set<Thread> threadSet = Thread.getAllStackTraces().keySet();

for (Thread thread: threadSet) {
 System.out.println(thread.getId());
}

Make sure you read and understand the method Thread.getAllStackTraces() before using them.

Answer 2

Use Thread.currentThread().getId();

Answer 3

Assign the thread object to a public variable if you need to control the thread from other parts of the program, or print it out directly if you just want to know what's running:

public int myThreadId = 0;

public void run () {

System.out.println("Thread Name: " + Thread.currentThread().getName(); // Printing the thread name

myThreadId = Thread.currentThread().getId(); // Assigning the thread ID to a public variable

}

Read more: How to Get a Reference to a Java Thread | eHow.com http://www.ehow.com/how_6879305_reference-java-thread.html#ixzz2FfEUe3cF

Also

Get a handle to the root ThreadGroup, like this:

ThreadGroup rootGroup = Thread.currentThread( ).getThreadGroup( );
ThreadGroup parentGroup;
while ( ( parentGroup = rootGroup.getParent() ) != null ) {
    rootGroup = parentGroup;
}

Now, call the enumerate() function on the root group repeatedly. The second argument lets you get all threads, recursively:

Thread[] threads = new Thread[ rootGroup.activeCount() ];
while ( rootGroup.enumerate( threads, true ) == threads.length ) {
    threads = new Thread[ threads.length * 2 ];
}

Note how we call enumerate() repeatedly until the array is large enough to contain all entries.