### Question:
StringUtils { public static String defaultString(final Object str) { return toString(str, EMPTY); }  static boolean isEmpty(CharSequence cs); static boolean isNotEmpty(CharSequence cs); static boolean isBlank(CharSequence cs); static boolean isNotBlank(CharSequence cs); static String defaultString(final Object str); static String toString(Object o, String defaultVal); static String toString(Object o); static final String EMPTY; }### Answer:
@Test public void defaultString() { Assert.assertEquals("", StringUtils.defaultString(null)); Assert.assertEquals("x", StringUtils.defaultString("x")); }