How to Enable and Disable JIT(Just-in-Time) in java ? Can we do it in Eclipse compiler ? If yes how to do? Explain Clearly

JIT compiler is enabled by default and it will be activated by calling a method. JIT starts at the same time as the VM, you can only modify JIT behavior at startup.

There are a number of ways to disable the JIT:

Specify -Djava.compiler=NONE on the command line.
Specify -Xint on the command line, which turns off the JIT and AOT compiler. To eliminate problems with one or the other you can turn these compilers off selectively with the -Xnojit and -Xnoaot options.
Call the java.lang.Compiler API programmatically.