### Question:
StringUtil { public static boolean isWhitespace(String text) { if (isNullOrEmpty(text)) { return false; } for (char ch : text.toCharArray()) { if (!Character.isWhitespace(ch)) { return false; } } return true; }  @SuppressWarnings("CStyleArrayDeclaration") static String capitalize(String text); @SuppressWarnings("CStyleArrayDeclaration") static String decapitalize(String text); static String fromSnakeCaseToCamelCase(String text); static String fromCamelCaseToSnakeCase(String text); static String fromCamelCaseToSnakeCaseWithLenient(String text); static boolean isWhitespace(String text); static String trimWhitespace(String text);  }### Answer:
@Test public void testIsWhitespace() { assertFalse(StringUtil.isWhitespace("")); assertTrue(StringUtil.isWhitespace(" ")); assertTrue(StringUtil.isWhitespace(" ")); assertTrue(StringUtil.isWhitespace(" \t")); }