Stack Implementation Java(Using Linked List)

Source code download here.

	package data.structures.Stack;
	import data.structures.LinkedList.LinkedList;
	import data.structures.LinkedList.Node;
	/**
	*
	* @author jasleen
	* @param <T>
	*/
	public class Stack<T> {
	final LinkedList<T> list;
	public Stack() {
	list=new LinkedList<>();
	}
	public void push(T t)
	{
	list.addAtHead(t);
	}
	public void pop()
	{
	if(!isEmpty())
	list.removeHead();
	else
	System.out.println("There is no item to pop");
	}
	public Node extractTop()
	{
	Node t=list.head();
	pop();
	return t;
	}
	public T top()
	{
	if(isEmpty())
	{
	System.out.println("There is no item");
	return null;
	}
	return list.head().key();
	}
	@Override
	public String toString() {
	StringBuilder builder=new StringBuilder();
	builder.append("[");
	builder.append("\t");
	Node currentTraversing=list.head();
	while(currentTraversing!=null)
	{
	builder.append(currentTraversing.key().toString());
	builder.append("\t");
	currentTraversing=currentTraversing.next();
	}
	builder.append("]");
	return builder.toString();//To change body of generated methods, choose Tools | Templates.
	}
	public boolean isEmpty() {
	return list.head()==null; //To change body of generated methods, choose Tools | Templates.
	}
	}

Linked List Implementation Java

Download Source Code LinkedList.java and Node.java

Check if given LinkedList is a pallindrome or not

Check if given LinkedList is a pallindrome or not

My version of the program. Open to corrections and improvements

/*
	* To change this license header, choose License Headers in Project Properties.
	* To change this template file, choose Tools | Templates
	* and open the template in the editor.
	*/
	package interview.practice;
	import data.structures.LinkedList.LinkedList;
	import data.structures.LinkedList.Node;
	import data.structures.Stack.Stack;
	/**
	*
	* @author jasleen
	*/
	public class isPallindrome {
	public static boolean isPallindrome(LinkedList list) {
	Node single = list.head(), doubl = list.head();
	Stack stack = new Stack();
	if (single == null||single.next()==null) {
	return false;
	}
	while (single.next() != null && doubl.next().next() != null) {
	stack.push(single.key());
	single = single.next();
	doubl = doubl.next().next();
	if ( doubl.next() == null) {
	break;
	}
	}
	System.out.println(doubl);
	System.out.println(single);
	System.out.println(stack);
	if (doubl.next()!= null) {
	stack.push(single.key());
	single = single.next();
	Node popped=stack.extractTop();
	if (!single.key().toString().equals(popped.key().toString())) {
	System.out.println("Returning at key" + popped.key().toString()+single.key());
	return false;
	}
	}
	single = single.next();
	System.out.println(stack);
	//System.out.println(single.key());
	while (single != null) {
	Node popped=stack.extractTop();
	if (!single.key().toString().equals(popped.key().toString())) {
	System.out.println("Returning at key" + popped.key().toString()+single.key());
	return false;
	}
	single = single.next();
	}
	return true;
	}
	}

Download code for this program here.

Download code for LinkedList here.

Download code for Node here.

Download code for Stack here.