Multithreading in Java is a technique that allows multiple threads (smaller units of a process) to run concurrently within a program, thereby making better use of the CPU and improving the overall performance of an application. It allows multiple tasks to be executed at the same time in a single program, making it suitable for performing complex or resource-heavy tasks concurrently.
In Java, threads are lightweight processes, and each thread has its own execution path. Java provides built-in support for multithreading through the Thread class and the Runnable interface.
Example: Using the Thread class
//Main.java file
class MyThread extends Thread {
@Override
public void run() {
for (int i = 0; i < 2; i++) {
System.out.println(Thread.currentThread().getId() + " Value " + i);
}
}
}
public class Main {
public static void main(String[] args) {
// Create two threads
MyThread t1 = new MyThread();
MyThread t2 = new MyThread();
// Start both threads
t1.start();
t2.start();
}
}
Output:
15 Value 0
15 Value 1
14 Value 0
14 Value 1
15 Value 1
14 Value 0
14 Value 1
Example: Using the Runnable interface
//Main.java file
class MyRunnable implements Runnable {
@Override
public void run() {
for (int i = 0; i < 2; i++) {
System.out.println(Thread.currentThread().getId() + " Value " + i);
}
}
}
public class Main {
public static void main(String[] args) {
// Create a Runnable object
MyRunnable myRunnable = new MyRunnable();
// Create two threads using the Runnable object
Thread t1 = new Thread(myRunnable);
Thread t2 = new Thread(myRunnable);
// Start both threads
t1.start();
t2.start();
}
}
Output:
15 Value 0
15 Value 1
14 Value 0
14 Value 1
15 Value 1
14 Value 0
14 Value 1