AtomicInteger is a class in Java that provides atomic operations on an int value. It is part of the java.util.concurrent.atomic package and can be used to perform thread-safe operations on a shared integer variable.

An AtomicInteger can be used in a multithreaded environment where multiple threads need to access and modify the same integer value. Some of the key methods available in the AtomicInteger class are:

• get(): returns the current value of the integer
• set(int newValue): sets the value of the integer to the specified value
• compareAndSet(int expect, int update): atomically sets the value of the integer to the specified update value if the current value is equal to the specified expect value
• incrementAndGet(): atomically increments the value of the integer and returns the new value
• decrementAndGet(): atomically decrements the value of the integer and returns the new value
• getAndAdd(int delta): atomically adds the specified delta value to the integer and returns the previous value

Here's an example of using AtomicInteger in Java:

import java.util.concurrent.atomic.AtomicInteger;

public class Example {
    public static void main(String[] args) {
        // create a new atomic integer with an initial value of 0
        AtomicInteger counter = new AtomicInteger(0);

        // increment the counter
        int value1 = counter.incrementAndGet();
        System.out.println("Value1: " + value1);

        // add 5 to the counter
        int value2 = counter.getAndAdd(5);
        System.out.println("Value2: " + value2);

        // check the value of the counter
        int value3 = counter.get();
        System.out.println("Value3: " + value3);
    }
}

In this example, we create a new AtomicInteger with an initial value of 0. We then use the incrementAndGet() method to atomically increment the value of the integer, and the getAndAdd() method to atomically add 5 to the integer and return the previous value.

Finally, we use the get() method to check the current value of the integer.

AtomicInteger is a useful class for situations where multiple threads need to access and modify the same integer value in a thread-safe manner. It can be used in a variety of applications, such as counting, synchronization, and more.