Java Performance

Java performance is the performance of a compiled Java program. This depends on how optimally its particular tasks are managed by the host Java Virtual Machine (JVM), and how well the JVM takes advantage of the features of the hardware and OS in doing so. Thus, any Java performance test or comparison has to always report the version, vendor, OS and hardware architecture of the used JVM. In a similar manner, the performance of the equivalent natively compiled program will depend on the quality of its generated machine code, so the test or comparison also has to report the name, version and vendor of the used compiler, and its activated optimization directives.

Historically, the execution speed of Java programs improved significantly due to the introduction of Just-In Time compilation (JIT) (in 1997/1998 for Java 1.1), the addition of language features supporting better code analysis, and optimizations in the JVM itself (such as HotSpot becoming the default for Sun's JVM in 2000). Hardware execution of Java bytecode, such as that offered by ARM's Jazelle, can also offer significant performance improvements.