In the Java heap, what do garbage collectors do?

• A. Move objects to permanent generation
• B. Destroy objects immediately
• C. Move objects from young generation heap to old generation heap
• D. Create new objects in old generation

Answer: (C)

Garbage collection in the JVM works by reclaiming memory from objects that are no longer reachable from any root reference. The heap is divided into generations, with new objects allocated in the young generation. Most objects die young, so the collector runs frequently there to reclaim space. Objects that survive several collections in the young generation are promoted to the old generation. This process—moving live objects from the young generation to the old generation—is how the GC handles long-lived data and reduces the cost of repeated collections. Objects aren’t destroyed immediately; unreachable ones are reclaimed, while reachable ones stay allocated. New objects start in the young generation, not the old. The idea of a separate permanent generation is outdated in modern JVMs.