Editing Java virtual machine (section)

===Bytecode instructions===
{{Main|Java bytecode}}

The JVM has [[instruction (computer science)|instructions]] for the following groups of tasks:

{{flatlist|
* [[Load/store architecture|Load and store]]
* [[Arithmetic]]
* [[Type conversion]]
* [[dynamic memory allocation|Object creation and manipulation]]
* [[stack (abstract data type)|Operand stack management (push / pop)]]
* [[branch (computer science)|Control transfer (branching)]]
* [[subroutine|Method invocation and return]]
* [[exception handling|Throwing exceptions]]
* [[monitor (synchronization)|Monitor-based concurrency]]
}}

The aim is binary compatibility. Each particular host [[operating system]] needs its own implementation of the JVM and runtime. These JVMs interpret the bytecode semantically the same way, but the actual implementation may be different. More complex than just emulating bytecode is compatibly and efficiently implementing the [[Java Class Library|Java core API]] that must be mapped to each host operating system.

These instructions operate on a set of common {{vanchor|abstracted [[data type]]s|DATA_TYPE}} rather the [[native data type]]s of any specific [[instruction set architecture]].