'''Java bytecode''' is the form of instructions that the [[Java virtual machine]] executes. it is nothing but a binary representation of the source code.Each [[bytecode]] instruction or opcode is one byte in length, however not all of the possible 256 instructions are used. In fact, [[Sun Microsystems]], the original creators of the [[Java (programming language)|Java programming language]], the [[Java virtual machine]] and other components of the Java Runtime Environment (JRE), have set aside a number of values to be permanently unimplemented.{{Fact|date=June 2008}}
