Java Thread setPriority() method

The setPriority() method of thread class is used to change the thread's priority. Every thread has a priority which is represented by the integer number between 1 to 10.

Thread class provides 3 constant properties:

public static int MIN_PRIORITY: It is the maximum priority of a thread. The value of it is 1.
public static int NORM_PRIORITY: It is the normal priority of a thread. The value of it is 5.
public static int MAX_PRIORITY: It is the minimum priority of a thread. The value of it is 10.

We can also set the priority of thread between 1 to 10. This priority is known as custom priority or user defined priority.

Syntax

Parameter

a: It is the priority to set this thread to.

Return

It does not return any value.

Exception

IllegalArgumentException: This exception throws if the priority is not in the range MIN_PRIORITY to MAX_PRIORITY.

SecurityException: This exception throws if the current thread cannot modify this thread.

Example 1: Maximum Priority Thread

public class JavaSetPriorityExp1 extends Thread
{  
    public void run()
    {  
        System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());  
    }  
    public static void main(String args[])
    {  
        // creating one thread 
        JavaSetPriorityExp1 t1=new JavaSetPriorityExp1();  
        // print the maximum priority of this thread
        t1.setPriority(Thread.MAX_PRIORITY);  
        // call the run() method
        t1.start();  
    }  
}

Test it Now

Output:

Priority of thread is: 10

Example 2: Minimum Priority Thread

public class JavaSetPriorityExp2 extends Thread
{  
    public void run()
    {  
        System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());  
    }  
    public static void main(String args[])
    {  
        // creating one thread 
        JavaSetPriorityExp2 t1=new JavaSetPriorityExp2();  
        // print the minimum priority of this thread
        t1.setPriority(Thread.MIN_PRIORITY);  
        // This will call the run() method
        t1.start();  
    }  
}

Test it Now

Output:

Priority of thread is: 1

Example 3: Normal Priority Thread

public class JavaSetPriorityExp3 extends Thread
{  
    public void run()
    {  
        System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());  
    }  
    public static void main(String args[])
    {  
        // creating one thread 
        JavaSetPriorityExp3 t1=new JavaSetPriorityExp3();  
        // print the normal priority of this thread
        t1.setPriority(Thread.NORM_PRIORITY);  
        // starting the thread 
        t1.start();  
    }  
}

Test it Now

Output:

Priority of thread is: 5

Example 4: User define Priority Thread

public class JavaSetPriorityExp4 extends Thread
{  
    public void run()
    {  
        System.out.println("running...");  
    }  
    public static void main(String args[])
    {  
        // creating one thread 
        JavaSetPriorityExp4 t1=new JavaSetPriorityExp4();  
        JavaSetPriorityExp4 t2=new JavaSetPriorityExp4();
        // set the priority
        t1.setPriority(4);
        t2.setPriority(7);
        // print the user defined priority 
        System.out.println("Priority of thread t1 is: " + t1.getPriority()); //4
        System.out.println("Priority of thread t2 is: " + t2.getPriority()); //7
        // this will call the run() method
        t1.start();
    }
}

Test it Now

Output:

Priority of thread t1 is: 4
Priority of thread t2 is: 7
running...

Example 5: When priority is greater than 10

public class JavaSetPriorityExp5 extends Thread
{  
    public void run()
    {  
        System.out.println("running...");  
    }  
    public static void main(String args[])
    {  
        // creating one thread 
        JavaSetPriorityExp5 t1=new JavaSetPriorityExp5();  
        JavaSetPriorityExp5 t2=new JavaSetPriorityExp5();
        // set the priority
        t1.setPriority(12);
        t2.setPriority(7);
        // print exception because priority of t1 is greater than 10
        System.out.println("Priority of thread t1 is: " + t1.getPriority()); 
        System.out.println("Priority of thread t2 is: " + t2.getPriority()); 
        // call the run() method
        t1.start();
    }
}

Test it Now

Output:

Exception in thread "main" java.lang.IllegalArgumentException
	at java.lang.Thread.setPriority(Thread.java:1089)
	at JavaSetPriorityExp5.main(JavaSetPriorityExp5.java:13)

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