void equalsTests() {
        System.out.println("\n---- equals tests ----");
        StringsList stringsList1 = new StringsList();
        StringsList stringsList2 = new StringsList();
        String str1 = "";
        String str2 = "";
        for (Integer i = 0; i < 5; i++) {
            for (int j = 0; j < 5; j++) {
                str1 += i;
                str2 += i;
            }
            stringsList1.add(str1);
            stringsList2.add(str2);
            str1 = "";
            str2 = "";
        }

        System.out.println("stringsList1 = " + stringsList1);
        System.out.println("stringsList2 = " + stringsList2);
        System.out.println("equals test: " + stringsList1.equals(stringsList2));

        //stringsList2.set(3, "7");
        //stringsList2.add("");
        stringsList2.set(3, "33733");
        System.out.println("stringsList1 = " + stringsList1);
        System.out.println("stringsList2 = " + stringsList2);
        System.out.println("equals test: " + stringsList1.equals(stringsList2));

        System.out.println("iterator usage:");
        Iterator<String> strIter = stringsList2.iterator();
        while (strIter.hasNext()) {
            System.out.print(strIter.next() + ". ");
        }
    }