java memory management 内存管理

Stacks in JVM

• A running Java thread has a private stack, called the Java method stack
  • has frames of the currently active invocations of methods
  • a frame stores the current values of the local variables, parameters, and information on calling method
• Program counter maintains the address of currently excuting statement
• At the top of the Java stack is the frame of the running method,remaining elements of the stack are frames of the suspended methods
• Using a stack allows programs to use recursion
• Arithmetic expressions are eveluated by the JVM using an operand stack
  

  Memory Heap

• Memory for an object is allocated dynamically by new operator
• Memory heap is for object’s memory
  

  Memory Allocation Algorithms

• Free list: a linked list joining holes of available free memory