ThreadPoolWithRunnable.java

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ThreadPoolWithRunnable {
    //Executor maintains thread pool to improve application performance by avoiding the continuous spawning of threads.
    //It executes the task bu running necessary threads from the pool.

    static final int MAX_T = 10; //Thread Pool Size
    static int i = 0;

    public static void main(String abc[]) {
        Runnable r1 = new Thread_1();

        // creates a thread pool with MAX_T no. of threads for concurrent execution

        ExecutorService pool = Executors.newFixedThreadPool(MAX_T);

        // passes the Task objects to the pool to execute

        for (i = 0; i < 20; i++) {
            pool.execute(r1); //Executes by picking non-running thread from the pool.
        }

        pool.shutdown();
    }
}

class Thread_1 implements Runnable {
    private int name;

    public Thread_1() {}

    public void run() {
        try {
            System.out.println(
                "Thread " +
                java.lang.Thread.currentThread().getId() +
                " is running"
            );
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}