The Just-In-Time compiler is one of the integral parts of the Java Runtime Environment. It is mainly responsible for performance optimization of Java-based applications at run time or execution time. In general, the main motto of the compiler is increasing the performance of an application for the end user and the application developer.
Deep Dive into JIT in Java
Byte code is the chief potential of Java’s WORA (Write once, run anywhere) environment. Speed of the Java application depends on the way the byte code gets converted to the native machine code. The bytecode can either be interpreted or compiled to native code or directly executed on the processor. But, if the bytecode is interpreted, it directly affects the speed of the application.
In order to speed up the performance, JIT compiler communicates with JVM at the execution time in order to compile byte code sequences into native machine code. Basically, when using JIT Compiler, the native code is easily executed by the hardware when compared to JVM Interpreter. By doing so, there will be a huge gain in execution speed.
When the JIT Compiler compiles the series of byte code, it also performs certain optimizations such as data analysis, translation from stack operations to register operations, eliminating subexpressions, etc. This makes Java very efficient when it comes to execution and performance.
If you wish to know more about JIT Compiler, you can read this article: