hey guys I need help to implement a array list I have the skeleton structure written out but some of the methods do not work and I have troubles with the remove method please help and how do you do isEmpy method

//tried my best dont get some stuff 
public class ArrayList{
	private Object[] array;
	private int position;
		this.array = new Object[15];
		this.position = 0;
	//apprently this does not work and my next add method works....strange
	public void add(Object o){

		array[this.position]= o;
	public void add(int index, Object o){
			Object[] tempArray = null;
			tempArray = array;
			array = new Object[index + array.length*2];
			System.arraycopy(tempArray, 0, array, 0, tempArray.length);
	public void clear(){
		for(int i=0;i<array.length;i++){
			array[i] = null;
	public boolean contains(Object o){
		for(int i = 0; i<array.length;i++)
			if(this.array[i] == o) return true;
		return false;
	public Object get(int index){
		return this.array[index];
	public int  indexOf(Object o){
		for(int i = 0; i<array.length; i++)
			if(this.array[i] == o) return i;
		return 0;
	public boolean isEmpty(){
		return true;
	public int lastIndexOf(Object o){
		for(int i = array.length - 1; i>=0;i--)
			if(array[i]==o) return i;
		return 0;
	public boolean remove(Object o){
		return true;
	public int size(){
		return array.length;
	public boolean remove(int index){
		return true;
	public Object set(int index, Object o){
		o = array[index];
		array[index] = o;
		return o;


please help me on fixing my code thank you so much people

6 Years
Discussion Span
Last Post by Slimmy

A couple of notes:

1. I see no problem with

public void add(Object o){
  array[this.position] = o;

2. The if-statement in your second add() method is wrong

3. You should do some check on the index in several of the methods

4. indexOf()/lastIndexOf() shouldn't return 0 if object isn't found

5. isEmpty() is not implemented

6. The remove() methods should simply do what the clear() method does, but for one/multiple elements

7. size() method returns the length of the array, not the number of objects in the "ArrayList"

8. You are checking equality with "==", that will most likely cause problems

Edited by Slimmy: spelling


but the second add method works

And you know this how? You tried to add one element and the program did not complain?
Check my previous points.

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