'''Java bytecode''' is the form of instructions that the [[Java virtual machine]] executes. Each [[bytecode]] instruction or opcode is one byte in length (hence the name), thushowever thenot numberall of bytecodesthe is limited topossible 256. Not all 256 possible bytecodevaluesinstructions 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, have set aside a number of values to be permanently unimplemented.