If you were designing a GC, what approaches to garbage collection do you know besides traversing the reachability graph?

In addition to the classic reachability graph traversal (mark-and-sweep), there are other approaches to garbage collection (GC):

• Reference Counting: each object maintains a reference count, which increases when a new reference is created and decreases when it is deleted. When the count reaches zero, the object is removed. The drawback is issues with cyclic references.

• Copying Collector: memory is divided into two areas, active and reserve. Live objects are copied from the active to the reserve area, after which the active area is completely cleared. This simplifies memory management and reduces fragmentation.

• Generational GC: memory is divided into generations (young, old, etc.), as most objects do not live long. The young generation is collected more frequently and quickly, while the old one less so.

• Incremental and Concurrent GC: garbage collection is performed in parts or in parallel with application work to reduce pauses.

• Region-based GC: memory is divided into regions, and garbage collection occurs per region, allowing for more flexible memory management.