从LinkedList的索引处删除元素

Question

I'm looking to clarify something regarding removing elements from a LinkedList. Given this code:

public boolean remove(int index)
{
    // if the index is out of range, exit
    if(index < 1 || index > size())
        return false;

    Node current = head;
    for(int i = 1; i < index; i++)
    {
        if(current.getNext() == null)
            return false;

        current = current.getNext();
    }
    current.setNext(current.getNext().getNext());
    listCount--; 
    return true;
}

From what I can see, this code ends up at the element before the one you want to remove. It then assigns the 'next' field to the node after the one you want to remove. My question is, do you not need to assign the 'next' field of the node you want to remove to null? I am a bit confused because it looks like the 'next' field still points to the element after, so you have 2 nodes pointing to it.

Any help would be appreciated.

Answer 1

do you not need to assign the 'next' field of the node you want to remove to null?

There is no good reason to do this in Java.

I am a bit confused because

You must be thinking of how another language like C++ works, where you have to do this to clear a smart pointer as it uses reference counts.

In Java, a reference is just a 4-byte pointer (or index to an Object)

it looks like the 'next' field still points to the element after, so you have 2 nodes pointing to it.

It's an object which has no references to it so it effectively doesn't exist. All it does is waste a bit of memory until the garbage collector cleans it up.

Answer 2

it looks like the 'next' field still points to the element after

It's not important, since nothing is pointing to the removed node it will be eventually automatically deleted by the garbage collector.