rendered paste bodypackage alteKlausur;class Stack { private Node first; private Node last; public void push(Object o) { if (first == null) { first = new Node(o); last = first; return; } else { last.setNext(new Node(o)); last = last.getNext(); } } public Object pop() { if (first == null) { return null; } if (first == last) { Object temp = first.getObject(); first = null; return temp; } Object otmp = last.getObject(); Node temp = first; while (temp.getNext().getObject() != otmp) { temp = temp.getNext(); } last.setNext(null); last = temp; return otmp; }}class Node { private Object o; private Node next; public Node(Object o) { this.o = o; } public void setNext(Node next) { this.next = next; } public void setObject(Object o){ this.o = o; } public Object getObject() { return o; } public Node getNext(){ return next; }}