ServerUtils { public String toLowerAlphaNumeric(String str) { return str.replaceAll("[^A-Za-z0-9 ]", "").trim().toLowerCase(); }  String toLowerAlphaNumeric(String str); String clean(String string); boolean isValid(String string);  }
@Test public void testToLowerAlphaNumeric() { Assert.assertEquals(utils.toLowerAlphaNumeric(str), expected); }