m1.addElement("A");
harness.check(m1.lastIndexOf("A", 6), 6);
harness.check(m1.lastIndexOf("A", 5), 0);
harness.check(m1.lastIndexOf("B", 6), 5);
harness.check(m1.lastIndexOf("B", 5), 5);
harness.check(m1.lastIndexOf("B", 4), 1);
harness.check(m1.lastIndexOf(null, 4), 3);
harness.check(m1.lastIndexOf(null, 3), 3);
harness.check(m1.lastIndexOf(null, 2), -1);
harness.check(m1.lastIndexOf("Z", 0), -1);
harness.check(m1.lastIndexOf("Z", -1), -1);