Java AtomicLong compareAndSet() Method

The compareAndSet() method of java AtomicLong class compares the current value of the AtomicLong instance to an expected value and if the two values are equal, it sets a new value for the AtomicLong instance.

Syntax

Parameters

expectedValue - The expected value

newValue - The new value

Example 1

import java.util.concurrent.atomic.AtomicLong;

public class AtomicLongCompareAndSetExample1 {
	
	public static void main (String [] args) {
		AtomicLong atomiclong = new AtomicLong(111);
		long expectedValue = 11;
		long newValue      = 222;
		atomiclong.compareAndSet(expectedValue, newValue);
		//Since Initialized value and expected value are not equal prints the initialized value
		System.out.println(atomiclong);
	}

}

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Output:

Example 2

import java.util.concurrent.atomic.AtomicLong;

public class AtomicLongCompareAndSetExample2 {
	
	public static void main (String [] args) {
		AtomicLong atomiclong = new AtomicLong(111);
		long expectedValue = 111;
		long newValue      = 222;
		atomiclong.compareAndSet(expectedValue, newValue);
		//Since Initialized value and expected value are equal prints the new value
		System.out.println(atomiclong);
	}

}

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Output:

Example 3

import java.util.concurrent.atomic.AtomicLong;

public class AtomicLongCompareAndSetExample3 {
	
	public static void main (String [] args) {
		AtomicLong atomiclong = new AtomicLong();
		long expectedValue = 0;
		long newValue      = -1;
		atomiclong.compareAndSet(expectedValue, newValue);
		//Since Initialized value and expected value are equal prints the new value
		System.out.println(atomiclong);
	}

}

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Output:

-1

Example 4

import java.util.concurrent.atomic.AtomicLong;

public class AtomicLongCompareAndSetExample4 {
	
	public static void main (String [] args) {
		AtomicLong atomiclong = new AtomicLong(-10);
		long expectedValue = 10;
		long newValue      = -20;
		atomiclong.compareAndSet(expectedValue, newValue);
		//Since Initialized value and expected value are not equal prints the Initialized value
		System.out.println(atomiclong);
	}

}

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Output: