The sweep phase is a key part of the garbage collection process in memory management. The garbage collector is responsible for automatically freeing up memory that is no longer being used by the program.

During the sweep phase, the garbage collector scans the heap (the area of memory used for dynamic memory allocation) to identify any memory blocks that are no longer being used by the program. These blocks are then marked as free and added to the free list, which is a list of available memory blocks that can be allocated for future use.

The sweep phase is typically preceded by the mark phase, which involves marking all the live objects in the heap. The mark phase identifies which memory blocks are still in use and which are not. The sweep phase then identifies the memory blocks that are no longer in use and adds them to the free list.

Once the sweep phase is complete, the garbage collector can start allocating memory for new objects. The free list is used to keep track of which memory blocks are available for allocation.