Array-based unordered list implementation in Java
I would recommend using Log4j instead of System.out.println() with some meaningful message to the user. Also, you can implement locate() method as mentioned below to avoid initializing the flag 

private int locate(int data)
{
    int i = 0;
    int index = -1;
    while (i &lt; size())
    {
        if (data == nodeElements[i].getData())
        {
           index = i;
           break;
        }
        i++;
    }
    return index;
 }


Change: Use break; to come out of the loop rather than using flag to check it.