Is iinc atomic in Java?

Question

I know increment operation is not atomic in C++ without locking.

Will JVM add any lock on its implementation of iinc instruction?

Answer 1

It is not atomic. Here is the generated byte code for an post-increment of a static int:

0 getstatic 18;    // Load value of variable.
3 iconst_1;
4 iadd;
5 putstatic 18;    // Store value.