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Introduction to Multithreading

Multithreading allows a program to perform multiple tasks concurrently, improving performance and responsiveness. In Java, threads are lightweight processes that share the same memory space, making them ideal for parallel execution.

What Is Multithreading?​

Multithreading is a programming technique where multiple threads (smaller units of a process) run concurrently within a single program. Each thread performs a specific task independently or collaboratively.

Why Use Multithreading?​

  • Concurrency: Perform multiple tasks simultaneously.
  • Performance: Utilize multi-core processors effectively.
  • Responsiveness: Keep applications responsive while performing background tasks.

Example: Simple Multithreading​

Below is an example of two threads running concurrently:

class MyThread extends Thread {
    public void run() {
        for (int i = 1; i <= 5; i++) {
            System.out.println(Thread.currentThread().getName() + ": " + i);
            try {
                Thread.sleep(500); // Sleep for 500ms
            } catch (InterruptedException e) {
                System.out.println("Thread interrupted.");
            }
        }
    }
}

public class MultithreadingExample {
    public static void main(String[] args) {
        MyThread thread1 = new MyThread();
        MyThread thread2 = new MyThread();

        thread1.setName("Thread-1");
        thread2.setName("Thread-2");

        thread1.start(); // Start thread1
        thread2.start(); // Start thread2
    }
}

Output:

Thread-1: 1
Thread-2: 1
Thread-1: 2
Thread-2: 2
...

Explanation:

  • Two threads (thread1 and thread2) run concurrently, printing numbers from 1 to 5.
  • The start() method begins thread execution, invoking the run() method.