explain last five lines in detail

public void add(int index, Object obj) throws IndexOutOfBounds Exception { if( index > size || index < 0 ) throw new IndexOutOf Bounds Exception ("Index: + index + /* enter your code below */ DLNode toAdd = new DLNode(obj, null, null); DLNode current = head; for(int x = 0; x < index; x++) { current = current.getNext(); } toAdd.setNext (current.getNext()); current.getNext().setPrev(toAdd);| current.setNext (toAdd); toAdd.setPrev (current); size++; //this the Size: + size);