Java Platform: Difference between revisions

Revision as of 02:56, 10 April 2005

Revision as of 15:27, 12 April 2005

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== Java Runtime ==

The heart of the Java platform is the concept of a common "virtual" processor that executes machine code that is distinct from the machine code for the physical hardware. For example, a "native" application running on an Intel Pentium processor would use a completely different binary format from a Java application running on the same processor. The Java platform provides an [[interpreter (computer)|interpreter]] program, called the [[Java virtual machine]] or JVM, that translates the Java bytecode into native binary at run-time. This permits the same application to be run on any platform that has a virtual machine available.

The Java runtime also includes a special program called a [[just-in-time]] compiler. This program is capable of converting the Java [[bytecode]] into the lower-level native machine code for it's target platform. This process is done as the applications are first loaded into the virtual machine. This step is similar to the process used to create native applications, only delayed until run time. This allows the JIT compiler to target a specific host platform and hardware, even potentially optimizing the output code based on other knowledge of the current host.