What is JIT in Java?

JIT stands for (Just-in-Time) compiler is a part of JRE(Java Runtime Environment), it is used for better performance of the Java applications during run-time. The use of JIT is mentioned in step by step process mentioned below:
Source code is compiled with javac to form bytecode
Bytecode is further passed on to JVM 
JIT is a part of JVM, JIT is responsible for compiling bytecode into native machine code at run time.
The JIT compiler is enabled throughout, while it gets activated when a method is invoked. For a compiled method, the JVM directly calls the compiled code, instead of interpreting it.
As JVM calls the compiled code that increases the performance and speed of the execution.