A garbage collector is a routine in many programming languages whose purpose is to free up space in the heap.

When programs run, they use two types of memories: stack (for local and short lived variables and functions) and heap (for longer lived values) heap-and-stack

Since reference type variables values (variables that only store a pointer to the actual value) are always stored in the heap, if a pointer is created in the stack, when that’s gone, the actual value is left unreferenced in the heap, occupying space.

The garbage collector will go through the heap and find values that aren’t being used anymore and clean them up.

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