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javajvmjit

why has JVM been given the name so? Is it because it acts as hardware like CPU?

1.Does JVM execute certain instructions without taking any help of CPU or it take help of CPU for all the instruction?

2.Is it like when JVM use JIT compiler then only it uses CPU for execution otherwise it executes the instruction itself when it uses interpreter?

  1. If JVM executes some instruction without CPU then give example of such kind of instruction and also instruction which can be executed by CPU only. Please explain the process of execution when JVM use interpreter and when it uses JIT compiler?
Solution

  • Why has JVM been given the name so?

    JVM stands for Java Virtual Machine. It has been named so, because it is a Virtual Machine designed for the purpose of running Java bytecode.

    Does JVM execute certain instructions without taking any help of CPU or it take help of CPU for all the instruction?

    The JVM itself is being run by the CPU. Do you consider that to be "taking help"? If so, then yes.

    When the JVM runs bytecode in "interpreted mode", it will take the action required without converting the bytecode to machine code that the CPU runs. As such, it can be considered to not "take help" of CPU. The interpreter itself is of course run by the CPU, so it's a toss-up what answer you're looking for.

    Is it like when JVM use JIT compiler then only it uses CPU for execution otherwise it executes the instruction itself when it uses interpreter?

    See previous answer.

    If JVM executes some instruction without CPU then give example of such kind of instruction and also instruction which can be executed by CPU only?

    All bytecode instructions can be interpreted. None of them must be JIT compiled to machine code.

    Please explain the process of execution when JVM use interpreter and when it uses JIT compiler.

    Way out of scope for StackOverflow to explain all that. There are books written for that.