java array reference

public class Minimal {
    public static void main(String args[]) {
        int[] a = new int[0];
        int[] b = new int[1];
        System.out.printf("len %d\n", a.length);
        changeRef(a);
        System.out.printf("len %d\n", a.length);
        a = b;
        System.out.printf("len %d\n", a.length);
    }

    public static void changeRef(int[] a) {
        int[] b = new int[1];
//      how do i change the a reference in this method?
        a = b;
    }
}
//return
//len 0
//len 0
//len 1