AtomicIntegerincrementAndGet

AtomicInteger.incrementAndGet is a method of the Java class java.util.concurrent.atomic.AtomicInteger. It atomically increments the current value by one and returns the updated value. The operation is designed for use in multi-threaded environments without explicit synchronization.

The method signature is public final int incrementAndGet(). It performs a read-modify-write using a compare-and-swap loop on the underlying volatile field, ensuring visibility and atomicity. After the call, all threads see the new value immediately.

This method differs from getAndIncrement, which returns the previous value before incrementing. incrementAndGet is commonly used for lightweight counters and sequence generators within concurrent code where the updated value is often needed right away.

Performance characteristics: It is non-blocking, but contention among threads can cause retries in the CAS loop. For simple increments, it is efficient, but in scenarios with very high contention, alternatives such as LongAdder may offer higher throughput, while AtomicInteger preserves a single shared value for reading and updating.

Example:

AtomicInteger ai = new AtomicInteger(0);

int v = ai.incrementAndGet(); // v is 1, ai.get() is 1

Notes: The operation provides atomic update for the contained value, but developers should ensure that multiple related updates across different atomic variables are coordinated, as incrementAndGet itself governs only the single AtomicInteger instance.