Confusion using Thread.sleep() method

Question

I tried it in this program
class NewThread implements Runnable {
  String name; // name of thread
  Thread t;
  NewThread(String threadname) {
    name = threadname;
    t = new Thread(this, name);
    System.out.println("New thread: " + t);
    t.start(); // Start the thread
  // This is the entry point for thread.
  public void run() {
    try {
      for(int i = 5; i > 0; i--) {
        System.out.println(name + ": " + i);
        Thread.sleep(1000);
    } catch (InterruptedException e) {
      System.out.println(name + "Interrupted");
    System.out.println(name + " exiting.");
class MultiThreadDemo {
  public static void main(String args[]) {
    new NewThread("One"); // start threads
    new NewThread("Two");
    new NewThread("Three");
    try {
      // wait for other threads to end
      Thread.sleep(10000);
    } catch (InterruptedException e) {
      System.out.println("Main thread Interrupted");
    System.out.println("Main thread exiting.");
}the output is
one: 5
two: 5
three 5
delay of 1 second
one:4
two: 4
three: 4
delay of 1second
what all i know about sleep() is that it pause the currently executing thread for specified time. hence in above program when first thread runs and prints value 5 then it should get paused for 1 second cause there is Thread.sleep(1000) after println() statement.
and output should be
one: 5
delay of 1 second
two: 5
delay of 1 second
three: 5
delay of 1 second
but this is not actually happens. may be i am wrong about Thread.sleep method() or something else.
would you guys please clear it?
regards
san

Answer 1

Thread.sleep() only sleeps the current thread. As each thread runs concurrently they all print concurrently and all sleep concurrently.