Can you explain what the term 'atomic variable' means in programming?

An atomic variable in programming is a variable for which operations are performed as indivisible (atomic) actions. This means that when working with such a variable, a race condition or partial update cannot occur — the operation either completes entirely or not at all.

In Java, for example, the AtomicInteger class from the java.util.concurrent.atomic package provides atomic operations on integer values, such as increment, decrement, compare, and swap. This allows safe manipulation of variables in a multithreaded environment without using locks.

Example of using AtomicInteger:

import java.util.concurrent.atomic.AtomicInteger;

public class Counter {
    private AtomicInteger count = new AtomicInteger(0);

    public void increment() {
        count.incrementAndGet(); // atomic increment
    }

    public int getCount() {
        return count.get();
    }
}

Here, incrementAndGet() guarantees that even when called simultaneously from multiple threads, the value will be correctly incremented without losing updates.