What is garbage collection in the JVM, and what fundamental problem does it solve compared to manual memory management (like in C/C++)?

Garbage collection automatically identifies and reclaims heap memory occupied by objects no longer reachable from any active reference (a local variable, static field, or another still-reachable object), freeing developers from manually tracking object lifetimes and explicitly deallocating memory -- this eliminates entire categories of memory bugs common in manually-managed languages, specifically use-after-free (accessing memory that's already been deallocated) and memory leaks caused by simply forgetting to free memory, though it introduces its own trade-offs like GC pause times and less predictable memory reclamation timing.

public void createObjects() {
    for (int i = 0; i < 1000; i++) {
        Object obj = new Object();  // allocated on the heap
    }  // once this loop iteration ends and 'obj' goes out of scope, the object becomes eligible for GC
    // No explicit free()/delete needed -- the garbage collector reclaims it automatically, eventually
}