@Test
 public void testRemoveDuplicateChars2() {
   String str;
   str = testClass.removeDuplicateChars2("Duplicatecharcheck");
   assertTrue("Unique chars check", testClass.findDuplicatesChars2(str));
   str = testClass.removeDuplicateChars2("abcd");
   assertTrue("Unique chars check", testClass.findDuplicatesChars2(str));
   str = testClass.removeDuplicateChars2("aaaa");
   assertTrue("Unique chars check", testClass.findDuplicatesChars2(str));
   str = testClass.removeDuplicateChars2("aaaabbb");
   assertTrue("Unique chars check", testClass.findDuplicatesChars2(str));
 }
 @Test
 public void testFindDuplicatesChars2() {
   assertTrue("Unique chars check", testClass.findDuplicatesChars2("length"));
   assertFalse("Duplicate char check", testClass.findDuplicatesChars2("seen"));
 }