Hello! So, I created my own Arraylist class called myArrayList.
I need to read a file that contains strings (which are just short phrases) into myArrayList.

I created a class called Phrase that are to be the objects that will be stored into the Arraylist. I also have a class called fileReader that simply reads the file.

I'm getting an Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at the grow() method in myArraylist
at add() method in myArraylist
at main() method

Here's my code:

public class myArrayList {
	private Object array[];  	
	private int totalSize;  // the capacity of the array
	private int currentItems;  // the number of items currently stored in the array
	public myArrayList(int n) {
		array = new Object[n];
		totalSize = n;
		currentItems = 0;

	public void add(Object i) {  // Add item to the end of the array list
		try {
			array[currentItems] = i;
		catch (ArrayIndexOutOfBoundsException a) {
			grow();        /****ERROR here*/
			array[currentItems++] = i;

	private void grow() {  // Doubles totalSize in array list
		Object[] newArray = new Object[2 * totalSize];    /****ERROR here*/
		for (int i = 0; i < currentItems; i++) {
			newArray[i] = array[i];
		array = newArray;
		totalSize = 2 * totalSize;
public class Phrase{
	private String phrase;

	public String getPhrase() {
		return phrase;

	public void setPhrase(String phrase) {
		this.phrase = phrase;
public static void main(String[] args) {
	myArrayList newArrayList = new myArrayList(20);
	fileReader myFileReader = new fileReader(

	Phrase myPhrase = myFileReader.readFile();
	Phrase newPhrase = new Phrase(myPhrase.getPhrase());
	while (myPhrase != null) {
		myArrayList.add(newPhrase);   /****ERROR here*/

I don't know if what I'm trying to do is even headed in the right direction. Also, I do not know how to test to see what is in myArrayList once I stop getting errors.

Later, I need to sort and remove duplicates in myArrayList.

Thanks in advance!

7 Years
Discussion Span
Last Post by sneaker


while (myPhrase != null) {
   myArrayList.add(newPhrase); /****ERROR here*/

is an endless loop. myPhrase is not null, you don't change its value inside the loop so it remains not null. Thus the loop will keep running forever and eventually you will run out of memory.

I don't know what the other classes do but:
1) You need to read inside the loop the next line
2) Search the forum on how to read a file using: Scanner or BufferedReader



while (myPhrase != null) {
      myArrayList.add(newPhrase); /****ERROR here*/

You are adding your new phrase to your class myArrayList, not your array[] and I suppose that you want your array[] to store your phrases.

I do not know how your file handler is build but if it takes line ( = every phrase is a new line) then it can work to write != null because when there is no more lines the result should be null. But test, read and try because javaAddict is much more experience than I am, so I can be totally wrong about this.

You can always write a simple test loop whit System.out.println() and ask it to print out for every array that is filled. This way you can see that you have got the phrases in your array[].

Good luck :)

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