Execution Engine

The execution engine is the most important part of JVM, it is responsible to execute Java bytecodes to the native language (machine language) which is understandable by the system (Processor Level ).
The two important components of the Execution Engine are

1-Interpreter
2-JIT (Just In Time Compiler)

1-Interpreter

The converted byte code assigned to various memory areas is passed to the execution engine. This function is responsible to read byte code line by line and convert into a native system instruction set which is executed by the processors.

2-JIT (JustInTime Compiler):

JIT compiler makes the task easy to read the same lines of code each time which is one of the biggest disadvantages of an interpreter. Below is the internal structure of the JIT Compiler. JIT compiler converts the byte codes into machine code after calling the runtime component.

For example: If you are executing the same line of code in the loop

for(int i=0;i<10;i++){

// Some Line of code

}

Fig.2

Fig.3