Thread has it’s own memory space

Each Java Virtual Machine thread has a private Java Virtual Machine stack, created at the same time as the thread.

Whereas Heap is shared across.

The Java Virtual Machine has a heap that is shared among all Java Virtual Machine threads.

References:

• Is there a stack space for every thread?

Boxing & UnBoxing

• Boxing?
  
  Converts expressions of primitive type to corresponding expressions of reference type.
  int intValue = 0;
  Integer intObject = intValue;bytecode:For Boxing Java compiler uses valueOf() instead of constructor. This is beneficial since it allows for caching, and doesn’t force the creation of a new object on each boxing operation.
  
  
• Un-Boxing?
  
  Converts expressions of reference type to corresponding expressions of primitive type.
  Integer intObject = new Integer(0);
  int intValue = intObject;
  
  bytecode:
  For Un-Boxing Java compiler uses intValue(), which Returns the value of this Integer as an int.

Reference:

• Internal workings bytecode Version
• Implicit Unboxing during equality Checking
• Simple Example for Boxing and UnBoxing
• https://youtu.be/VbMWqfEtbMo