In Java, garbage collection (GC) is the automatic process of reclaiming memory occupied by objects that are no longer in use. The JVM manages this process to ensure efficient memory utilization. The heap memory is divided into generations: Young Generation, Old Generation, and Metaspace.

Young Generation:

• Eden Space: New objects are initially allocated here.
• Survivor Spaces (S1 and S2): After surviving a minor GC cycle, objects are moved from Eden to these spaces.

Old Generation:

• Objects that survive multiple GC cycles in the Young Generation are promoted to the Old Generation, where they reside until they are no longer needed.

Metaspace:

• This area stores class metadata, replacing the Permanent Generation in Java 8 and later.

GC Types:

• Minor GC: Occurs in the Young Generation when the Eden Space fills up. It is generally fast and frequent.
• Major (or Full) GC: Involves the Old Generation and is less frequent but more time-consuming. It can trigger a minor GC as well.

GC Algorithms:

• Mark-and-Sweep: Marks reachable objects and sweeps away the unmarked ones.
• Copying: Used in the Young Generation, where live objects are copied to a survivor space.
• Mark-Compact: Marks live objects and compacts them to eliminate fragmentation.

The GC process is designed to minimize pauses and optimize performance, ensuring efficient memory management in Java applications.