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Java / JVM Architecture (Java21) Interview questions

Explain the internal working of the JVM stack frame during method invocation?

Each time a method is invoked, the JVM pushes a new frame onto the calling thread's JVM Stack, and pops it off when the method returns or throws.

Frame componentPurpose
Local variable arrayStores method parameters and local variables, indexed by slot number
Operand stackWorking space for intermediate values during bytecode execution
Constant pool referencePoints back to the current class's runtime constant pool, for resolving symbolic references
Frame dataBookkeeping for returning control to the caller and for exception-handling dispatch

Bytecode instructions operate almost entirely by moving values between the local variable array and the operand stack - for example, iload_0 pushes local slot 0 onto the operand stack, and iadd pops two values off it, adds them, and pushes the result back.

The operand stack within a frame is used for:
A frame's constant pool reference is used to:

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