Question

public class Array                                                               
{
    static String[] a = new String[] {"red", "green", "blue"};
    static Point[] p = new Point[] {new Point(1, 2), "3,4"};

    public static void main(String[] args)
    {
        System.out.println("hello");
    }

    class Point
    {
        int x;
        int y;

        Point(int x, int y)
        {
            this.x = x;
            this.y = y;
        }

        Point(String s)
        {
            String[] a = s.split(",");
            x = a[0].parseInt();
            y = a[1].parseInt();
        }
    }
}

In the above program, the static Point array initialization fails, reporting error:

Array.java:4: non-static variable this cannot be referenced from a static context
    static Point[] p = new Point[] {new Point(1, 2), "3,4"};  

But, the static String array succeeds. What’s the difference between them?

I really need a static object array, because it’s easy to refer to without instantiate the outer class.

Thanks

Answer 1

You’d need to make Point a static nested class, like this:

static class Point {