Java virtual machine
A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform.
| Designer | Sun Microsystems |
|---|---|
| Bits | 32-bit |
| Introduced | 1994 |
| Version | 20.0.1 |
| Type | Stack and register–register |
| Encoding | Variable |
| Branching | Compare and branch |
| Endianness | Big |
| Open | Yes |
| Registers | |
| General-purpose | Per-method operand stack (up to 65535 operands) plus per-method local variables (up to 65535) |
The JVM reference implementation is developed by the OpenJDK project as open source code and includes a JIT compiler called HotSpot. The commercially supported Java releases available from Oracle are based on the OpenJDK runtime. Eclipse OpenJ9 is another open source JVM for OpenJDK.