Strings { public static boolean isBlank(final String s) { return isEmpty(s) || s.trim().isEmpty(); } private  Strings(); static boolean isNull(final String s); static boolean isEmpty(final String s); static boolean isNotEmpty(final String s); static boolean isBlank(final String s); static String trim(final String s); static String trimToNull(final String s); static String trimToEmpty(final String s); static String toLowerCase(final String s);  }
@Test public void testIsBlank() { final String nullString = null; final String emptyString = ""; final String blankString = " "; final String string = "a"; assertThat(Strings.isBlank(nullString), is(true)); assertThat(Strings.isBlank(emptyString), is(true)); assertThat(Strings.isBlank(blankString), is(true)); assertThat(Strings.isBlank(string), is(false)); }