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'''Java bytecode''' is the form of instructions that the [[Java virtual machine]] executes. Each [[bytecode]] instruction is one byte in length (hence the name), thus the number of bytecodes is limited to no more than 256. Not all 256 possible bytecode values are used, in fact [[Sun Microsystems]], the original creators of the [[Java programming language]], the [[Java virtual machine]] and other components of the Java Runtime Environment, have permanently set aside a number of values to be permanently unimplemented. The bytecodes are given below.
A Java programmer does not need to be aware of or understand Java bytecode at all. However, as suggested in the IBM developerWorks journal, "Understanding bytecode and what bytecode is likely to be generated by a Java compiler helps the Java programmer in the same way that knowledge of assembler helps the C or C++ programmer."[http://www-128.ibm.com/developerworks/ibm/library/it-haggar_bytecode/]
If executing Java bytecode in a Java virtual machine is not desirable, a developer can also compile Java source code or Java bytecode directly to native machine code with tools such as the [[GCJ|GNU Compiler for Java]].
==The Java bytecodes==
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