Introduction to the location and function of each memory area of the Java Virtual machine

Java Virtual Runtime data area:

Relevant area Description:

Program Counter:

Function: The line number indicator of the byte code executed by the current thread. If the Java method records the instruction address, if the native method is not logged

Isolation: Thread Isolation

Error: None

Java Virtual machine stack :

Features: Describes the memory model that Java methods perform: Each method executes a stack frame that stores information such as local variable tables, operand stacks, dynamic links, method exits, and so on.

Isolation: Thread Isolation

Error: Stackoverflowerror exception is thrown when the stack depth of a thread request is greater than the depth allowed by the virtual machine;

The dynamic extension fails to request enough memory to throw a OutOfMemoryError exception.

Local Variables table: The memory space required for a local variable table is allocated during compilation, containing various basic data types, and object references.

Local method Stack:

　　Function: The native method service that is used by the virtual machine. (Virtual machine stack is a Java method (i.e. bytecode) service)

Isolation: Thread Isolation

Error:stackoverflowerror and OutOfMemoryError

Java heap:

　　Functions: Storing object instances

Isolation: Thread sharing

Error:outofmemoryerror

Subdivision: The angle of memory recycling: New generation, Laosheng generation

Memory allocation angle: The Java heap may divide multiple thread-private allocation buffers.

Virtual machine limit: No contiguous memory space required, can be fixed size or extensible

Method Area:

Features: Store class information, constants, static variables, even compiler-compiled code, that have been loaded by the virtual machine.

Isolation: Thread sharing

Error:outofmemoryerror

Virtual Machine Limitations: No contiguous memory space is required, can be fixed size or extensible, and this area of memory recycling is primarily for the collection of constant pools and unloading of types.

　　Run a constant pool: part of a method area

　　　　Functions: Used to store various literal and symbolic references generated during the compilation period, and direct references translated

Features: Dynamic, you can also put new constants into the pool during run time.

Error:outofmemoryerror

Introduction to the location and function of each memory area of the Java Virtual machine