The Thread Class

The Thread class in Java provides a direct way to create and manage threads. It belongs to the java.lang package and provides various methods to control thread behavior.

Creating a Thread Using Thread Class

To create a thread using the Thread class, extend it and override its run() method.

class MyThread extends Thread {
    public void run() {
        System.out.println("Thread is running.");
    }
}

public class Main {
    public static void main(String[] args) {
        MyThread t1 = new MyThread();
        t1.start();  // starts the thread
    }
}

Important Methods in Thread Class

MethodDescription
start()Starts the thread.
run()Contains the code executed by the thread.
sleep(ms)Puts thread to sleep for specified time.
join()Waits for a thread to die.
isAlive()Checks if the thread is still running.
setName()Sets the thread’s name.
getName()Returns the thread’s name.

Example with Sleep and Join

class MyThread extends Thread {
    public void run() {
        try {
            Thread.sleep(500);
            System.out.println("Thread " + Thread.currentThread().getName() + " running.");
        } catch (InterruptedException e) {
            System.out.println("Interrupted");
        }
    }
}

public class Main {
    public static void main(String[] args) throws InterruptedException {
        MyThread t1 = new MyThread();
        t1.setName("Worker1");
        t1.start();
        t1.join();  // Waits for t1 to finish
        System.out.println("Main thread finished.");
    }
}

Thread Priorities

Java threads have priorities that help the thread scheduler decide when each thread should run.

  • Constants: MIN_PRIORITY (1), NORM_PRIORITY (5), MAX_PRIORITY (10)
t1.setPriority(Thread.MAX_PRIORITY);

🔗 Related Notes