Garbage collection

● Garbage collection is the process of looking at heap memory, identifying which objects are in use and which are not, and deleting the unused objects.

● An in use object, or a referenced object, means that some part of your program still maintains a pointer to that object.

● An unused object, or unreferenced object, is no longer referenced by any part of your program.

Steps involved in garbage collection

● Marking● Normal deletion● Deletion with compaction

Generational garbage collection

Types of generational garbage collection● young generation objects● Old generation objects● Permanent generation objects

Steps involved in Generational garbage collection

● Object allocation● Filling the Eden space● Copying reference object● Object aging● Additional aging● promotion

Object allocation

Filling eden space

Copying reference objects

aging

Additional aging

Promotion

Sample code

Garbage collection output

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