A Java Virtual Machine (JVM), an implementation of the Java Virtual Machine Specification, interprets compiled Java binary code (called Bytecode) for a computer's processor (or 4.2.1.1 Hardware Platform) so that it can perform a Java program's instructions. Java was designed to allow application programs to be built that could be run on any platform without having to be rewritten or recompiled by the programmer for each separate platform. A JVM makes this possible because it is aware of the specific instruction lengths and other particularities of the platform.