Stack Implementation

public class Stack{
private java.util.ArrayList pool=new java.util.ArrayList();
public Stack(){
}
public Satck(int n){
pool.ensureCapacity(n);
}
public void clear(){
pool.clear();
}
public boolean isEmpty(){
return pool.isEmpty();
}
public Object topEl(){
if(isEmpty())
throw new java.util.EmptyStackExeception();
return pool.lastElement();
}
public Object pop(){
if(isEmpty())
throw new java.util.EmptyStackExeception();
retrun pool.remove(poo.size()-1);
}
public void push (Object El){
pool.add(El);
}
public String toString(){
return pool.toString();
}
}
public class AppStack{
private java.util.LinkedList List=new java.util.LinkedList();
public AppStack(){
}
public void clear(){
list.clear();
}
public boolean isEmpty(){
return list.isEmpty();
}
public Object topEl(){
if(isEmpty())
throw new java.util.EmptyStackExceptio();
return list.getLast();
}
public Object pop(){
if(isEmpty())
throw new java.util.EmptyStackException();
return list.removeLast();
}
public void push(Object El);
list.addLast(El);
}
public String toString(){
return list.toString();
}
}