public class Interner {

    public static void main(String[] args) {
        String[] ss = new String[4];
        ss[0] = "this";
        ss[1] = "this";
        ss[2] = new String("this");
        ss[3] = args[0];

        printEQ(ss);
        ss[3] = ss[3].intern();
        System.out.println("\n\nAfter interning ss[3]");
        printEQ(ss);
    }

    public static void printEQ(String[] ss) {
        System.out.format("%7s", "");
        for (int i = 0; i < ss.length; i++) {
            System.out.format("%7s", ss[i]);
        }
        for (int i = 0; i < ss.length; i++) {
            System.out.format("\n%7s", ss[i]);
            for (int j = 0; j < ss.length; j++) {
                if (j >= i) {
                    System.out.format("%7b", ss[i] == ss[j]);
                } else {
                    System.out.format("%7s", "");
                }
            }
        }
        System.out.println();
    }
}