Here is a code that displays the following pattern:

 1  2  3  4
 12 13 14 5
 11 16 15 6
 10 9  8  7

public class spiral{
    public static void main(String[] args) {
        int n=4;
        int a[][]=new int[n][n];
        int i,j,x=1,p=0,q=n-1;
        while(x<=(n*n))
        {
            for(i=p;i<=q;i++)
            {
                a[p][i]=x;
                x++;
            }
            for(i=(p+1);i<=q;i++)
            {
                a[i][q]=x;
                x++;
            }
            for(i=(q-1);i>=p;i--)
            {
                a[q][i]=x;
                x++;
            }
            for(i=(q-1);i>=(p+1);i--)
            {
                a[i][p]=x;
                x++;
            }
            p++;
            q--;
        }
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++)
            {
                System.out.print(a[i][j]+" ");
            }
            System.out.println();
        }
    }
}