JVM Basic Structure 1

1.JVM Start-up process

java XXX---> Mount configuration----> Find JVM.dll based on configuration---> Initialize JVM to get JNIEVN interface---> Find Main method and run

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Based on the current path JVM.dll the JVM JNIEVN as the JVM interface, Findclass

And the main implementations of the system version are implemented through it

Jvm.cfg

2.JVM of memory structure

3. PC Register

1) Each thread has a PC register

2) created when thread is created

3) point to the address of the next instruction

4) When you run the local method, the value of the PC is undefined

4. Method area

1) Save some information about the load class

--Constant pool of types

--Information on fields and methods

--Method byte code

2) usually associated with the permanent zone (PERM)

5. Java Heap

--closely related to the development of programs

--The objects in the application system are mainly stored in the heap

--All threads share the Java heap

-For generational GC, the heap is also generational

Main working range of--GC

6. Java stack

--Thread Private

--The stack is a series of frames (so the Java stack is also called the frame stack)

--frame holds local variables of a method (parameters and local variables of functions), operand stacks, Chang pointers

--each time a method call creates a frame and presses the stack

7. Java stack--operand stack

There are no registers in the--java, all parameters are passed with the operand stack

JVM Basic Structure 1