Thread Priority in Java with example

By
Rakesh
-

In this article, we will see about Thread Priority in Java with example. In multithreading, each thread has some priority. Even we write a simple hello world program, we have default thread (main thread) has default priority 5. If we create user defined threads JVM will assign default priority i.e 5 for these threads too.

Let’s see an example.

package threadpriority;
class MyThread1 extends Thread {
	public void run() {
		System.out.println("Name of current thread is  " + Thread.currentThread().getName());
		System.out.println("Priority of current thread is  " + Thread.currentThread().getPriority());

	}
}

public class ThreadPriorityExample {
	public static void main(String[] args) {
		MyThread1 thread1 = new MyThread1();
		thread1.start();
		System.out.println("Name of current thread is  " + Thread.currentThread().getName());
		System.out.println("Priority of current thread is  " + Thread.currentThread().getPriority());
	}
}

Output is –

Name of current thread is main
Priority of current thread is 5
Name of current thread is Thread-0
Priority of current thread is 5

Range of thread priority – The range of thread priority is between 1 to 10. There are three constant has been defined in thread class MIN_PRIORITY, NORM_PRIORITY and MAX_PRIORITY as below.

public final static int MIN_PRIORITY = 1;
public final static int NORM_PRIORITY = 5;
public final static int MAX_PRIORITY = 10;

Example –

package threadpriority;

public class ThreadPriorityExample {
	public static void main(String[] args) {
		System.out.println("Minimum priority of thread is "+Thread.MIN_PRIORITY);
		System.out.println("Normal priority of thread is "+Thread.NORM_PRIORITY);
		System.out.println("Maximum priority of thread is "+Thread.MAX_PRIORITY);
	}
}

Output is –

Minimum priority of thread is 1
Normal priority of thread is 5
Maximum priority of thread is 10

Setting a thread priority – We can set thread priority using setPriority() method.

package threadpriority;

public class ThreadPriorityExample {
	public static void main(String[] args) {
		System.out.println("Name of thread is :- "+Thread.currentThread().getName());
		System.out.println("Default priority of thread is :- "+Thread.currentThread().getPriority());
		System.out.println("----After setting priority----");
		Thread.currentThread().setPriority(8);
		System.out.println("Name of thread is :- "+Thread.currentThread().getName());
		System.out.println("Default priority of thread is :- "+Thread.currentThread().getPriority());
		
	}
}

Output is –

Name of thread is :- main
Default priority of thread is :- 5
—-After setting priority—-
Name of thread is :- main
Default priority of thread is :- 8

We can also define priority for user defined threads.

package threadpriority;
class MyThread1 extends Thread {
	public void run() {
		System.out.println(Thread.currentThread().getPriority());
	}
}

public class ThreadPriorityExample {
	public static void main(String[] args) {
		MyThread1 thread1 = new MyThread1();
		MyThread1 thread2 = new MyThread1();
		MyThread1 thread3 = new MyThread1();
		thread1.setPriority(6);
		thread2.setPriority(7);
		thread3.setPriority(8);
		thread1.start();
		thread2.start();
		thread3.start();
	}
}

Output is –

6
7
8

The sequence of output may vary. Since we are doing thread1.start(), thread2.start() and thread3.start() , run() method will call three times.

That’s all about Thread Priority in Java with example.

You may like.

Thread class docs.

RELATED ARTICLESMORE FROM AUTHOR