Identifying Atomic Operations in Java

In Java, an atomic operation is indivisible and guaranteed to complete without interruption from other threads. This provides strong consistency guarantees, which are crucial for ensuring data integrity in multithreaded applications.

Types of Atomic Operations

According to the official Java documentation, the following operations are considered atomic:

• Primitive assignments (except long and double): Assignments to byte, short, int, float, boolean, and char variables are atomic.
• Reference assignments: Assigning references to object variables is also atomic.
• Volatile variable assignments: Assignments to volatile variables enforce visibility and ordering across threads.

Additional Atomic Operations

• Atomic classes in java.concurrent.Atomic*: These classes provide atomic operations for compound operations and reference counting.

Limitations of Atomicity

64-bit Primitives (long and double):
While these operations are generally considered atomic on most CPUs, there may be architectures where this is not guaranteed.

Visibility:
Atomic operations do not imply visibility. Although a thread will not see a partially written primitive variable, it may not immediately observe the new value.

Conclusion:
Understanding atomic operations in Java is essential for building thread-safe and reliable applications. By employing these operations judiciously, developers can ensure that data modifications are always complete and consistent.