Generational

Garbage collection is performed on objects on basis of their age in the program.

Heap Memory Division

Generational garbage collector divides the heap memory into different generations based on the lifespan of objects.

Heap is divided into:

• Young Generation (Eden Space)
• Old Generation
• Survivor space
  • 1
  • 2

Garbage collection life cycle

• Objects are stored in Eden space, when they are created at first.
• 1st cycle - When Eden Space gets full
  • Minor GC runs
  • Objects moved to survivor space 1
• Susequent cycles - Eden space gets full again
  • Objects moved to survivor space 2 from both Eden space and survivor 1

💡 Objects keep moving between both survivor spaces in cycles

Objects older than Max tenure threshold (a certain threshold for number of cycles) are moved to old generation space.

• When old generation space is about to be full
• major GC runs → time consuming and might pause the application