What is JVM JIT?
Starting with Oracle 11g release 1 (11.1), there is a just-in-time (JIT) compiler for Oracle JVM environment. Based on dynamically gathered profiling data, this compiler transparently selects Java methods to compile the native machine code and dynamically makes them available to running Java sessions. Additionally, the compiler can take advantage of Oracle JVM’s class resolution model to optionally persist compiled Java methods across database calls, sessions, or instances. Such persistence avoids the overhead of unnecessary recompilations across sessions or instances, when it is known that semantically the Java code has not changed. The JIT compiler is controlled by a new boolean-valued initialization parameter called java_jit_enabled. When running heavily used Java methods with java_jit_enabled parameter value as true, the Java methods are automatically compiled to native code by the JIT compiler and made available for use by all sessions in the instance. For more details refer to th
