Java Memory Model

What is the Java memory model?

• References
  • Java memory model - Jenkov
  • Primitives stored on heap - Stack Overflow
  • Stack and Heap in Java - JavaRevisited

Java Memory Model

The JVM divides memory between thread stacks and the heap.

What is a thread stack?

• each thread has its own stack that consists of the following:
  • local variables
    • references to objects or the primitive data itself
  • each method on the call stack for that thread
• local primitive variables on the stack are only visible to the thread that owns it.
• local reference variables that point to objects on the heap are also only visible to the owning thread.

What is the heap?

• The heap contains all objects created by the application.
• Objects reside here regardless of which thread created them.
• Primitive member variables are stored on the heap, while local primitives are stored on the thread stack.
• Objects on the heap are visible to all threads.

Computer Hardware Memory

The Java Memory Model and how it maps to Computer Hardware Memory