Question

I have a question about how GC works in Java.
Consider the following code:

class C1 {
    ArrayList<int> myList = new ArrayList<int>();

    public void setList(ArrayList<int> l) {
         myList = l;
    }
}

func(C1 C) {
    ArrayList<int> l1 = new ArrayList<int>();
    l1.add(1);
    C.setList(l1);
}

main() {
    C1 C = new C1();
    func(C);
    ...
}

my question is:
does GC releases ‘l1’ after func() returns or not?

Answer 1

No, it doesn’t, because there’s a root reference (stack variable C) which has a strong reference (myList), to the new ArrayList. After main() returns, then the C1 and the ArrayList are collectible, because the root reference disappears.