Generic array in java

//MyArray.java
/* Copyright (c) 2013 Elias Daler

    This software is provided 'as-is', without any express or implied
    warranty. In no event will the authors be held liable for any damages
    arising from the use of this software.

    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:

    1. The origin of this software must not be misrepresented; you must not
    claim that you wrote the original software. If you use this software
    in a product, an acknowledgment in the product documentation would be
    appreciated but is not required.

    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original software.

    3. This notice may not be removed or altered from any source
    distribution.
*/

import java.lang.reflect.Array;

public class MyArray<T> {
    private T[] arr;
    private int size;

    @SuppressWarnings({"unchecked"})
    public MyArray(int s) {
        if(s <= 0) {
            throw new IndexOutOfBoundsException();
        }
        arr = (T[])new Object[s];
        size = s;
    }

    public void insert(T item, int index) {
        if(index >= size || index < 0) {
            throw new ArrayIndexOutOfBoundsException();
        }
        arr[index] = item;
    }

    public void insert(T item) {
        T[] arr_new = (T[])new Object[size + 1]; // create bigger array
        arr_new[size] = item; // insert item in the end
        for(int i = 0; i < size; i++) { // copy old array
            arr_new[i] = arr[i];
        }
        arr = arr_new;
        size++;
    }

    public T get(int index) {
        if(index >= size || index < 0) {
            throw new ArrayIndexOutOfBoundsException();
        }
        return arr[index];
    }

    public void remove(int index) {
        if(index >= size || index < 0) {
            throw new ArrayIndexOutOfBoundsException();
        }
        arr[size] = null;
    }

    public int size() {
        return size;
    }

    public String toString() {
        String str = new String();
        for(int i = 0; i < size; i++) {
            if(arr[i] != null) {
                str += arr[i].toString();
                if(i != size - 1) str += ", "; // don't add comma in the end
            } else {
                str += "null, ";
            }
        }
        return str;
    }

    @Override
    public boolean equals(Object o) {
        if(!(o instanceof MyArray)) return false;
        MyArray<T> second = (MyArray<T>)o;
        if(size != second.size())  {
            return false;
        }
        for(int i = 0; i < size; i++) {
            if(arr[i] != second.get(i)) return false;
        }
        return true;
    }

    public int hashCode() {
        return arr.hashCode();
    }
}

// main.java

public class Main {

    public static void main(String[] args) {
        MyArray<Integer> test = new MyArray<Integer>(10);
        test.insert(5, 2);
        test.insert(10, 3);
        test.insert(20);
        System.out.println(test.toString());
    }
}