How to get thread id from a thread pool?

Using Thread.currentThread():

private class MyTask implements Runnable {    public void run() {        long threadId = Thread.currentThread().getId();        logger.debug("Thread # " + threadId + " is doing this task");    }}

The accepted answer answers the question about getting a thread id, but it doesn't let you do "Thread X of Y" messages. Thread ids are unique across threads but don't necessarily start from 0 or 1.

Here is an example matching the question:

import java.util.concurrent.*;class ThreadIdTest {  public static void main(String[] args) {    final int numThreads = 5;    ExecutorService exec = Executors.newFixedThreadPool(numThreads);    for (int i=0; i<10; i++) {      exec.execute(new Runnable() {        public void run() {          long threadId = Thread.currentThread().getId();          System.out.println("I am thread " + threadId + " of " + numThreads);        }      });    }    exec.shutdown();  }}

and the output:

burhan@orion:/dev/shm$ javac ThreadIdTest.java && java ThreadIdTestI am thread 8 of 5I am thread 9 of 5I am thread 10 of 5I am thread 8 of 5I am thread 9 of 5I am thread 11 of 5I am thread 8 of 5I am thread 9 of 5I am thread 10 of 5I am thread 12 of 5

A slight tweak using modulo arithmetic will allow you to do "thread X of Y" correctly:

// modulo gives zero-based results hence the +1long threadId = Thread.currentThread().getId()%numThreads +1;

New results:

burhan@orion:/dev/shm$ javac ThreadIdTest.java && java ThreadIdTest  I am thread 2 of 5 I am thread 3 of 5 I am thread 3 of 5 I am thread 3 of 5 I am thread 5 of 5 I am thread 1 of 5 I am thread 4 of 5 I am thread 1 of 5 I am thread 2 of 5 I am thread 3 of 5 

You can use Thread.getCurrentThread.getId(), but why would you want to do that when LogRecord objects managed by the logger already have the thread Id. I think you are missing a configuration somewhere that logs the thread Ids for your log messages.