Just-In-Time (JIT) Compiler in Java: How Does It Work?

What is the primary function of a Just-In-Time (JIT) compiler in Java?

A) Converts Java source code into bytecode
B) Converts bytecode into platform-specific machine code
C) Converts bytecode into instructions for direct processor execution
D) Converts Java source code into instructions for direct processor execution

Answer:

A Just-In-Time (JIT) compiler in Java primarily converts bytecode into platform-specific machine code.

Explanation: The primary function of a Just-In-Time (JIT) compiler in Java is to convert bytecode into platform-specific machine code. Essentially, the JIT compiler serves as an intermediary, translating the bytecode (the output from the Java compiler) into native machine code just before it is executed. By doing this, it helps optimize the speed of execution and makes the Java program run faster on the specific platform.

The JIT compiler does not convert Java source code into bytecode (that's the task of the Java compiler), nor does it convert bytecode into direct processor instructions or Java source code into direct processor instructions. Those options do not accurately represent the role of a JIT compiler in Java.