are all instructions in jvm atomic?
jvm
Solution
The bytecode instructions you mentioned (`iinc`, `iload`, `aload` etc.) operate on the values from the operand stack and on the local variables. These areas are thread-local (see JVMS 2.5, 2.6), that is, speaking about atomicity here is meaningless. I.e. they are NOT implemented using atomic CPU instructions like `lock xadd`, but nobody should care.
The bytecode instructions that read or write fields and array elements (`getfield`, `putfiled`, `iastore` etc.) are atomic except for `long` and `double` types (see JLS 17.7). 32-bit JVM may implement (actually, HotSpot JVM does implement) reading and writing of 64-bit fields with two 32-bit loads or stores, unless the field is declared `volatile`.
Problem
I remember I read the somewhere before,but I can't find the offical document now. are all instructions in jvm all atomic? like: ``` iinc iload aload ``` all atomic?