OrchestratorUtils { public static boolean isEmpty(@Nullable String str) { return str == null || str.length() == 0; } private  OrchestratorUtils(); static void checkArgument(boolean expression, String errorMessageTemplate, @Nullable Object... errorMessageArgs); static void checkState(boolean expression, String errorMessageTemplate, @Nullable Object... errorMessageArgs); @CheckForNull static String defaultIfEmpty(@Nullable String object, @Nullable String defaultValue); @CheckForNull static T defaultIfNull(@Nullable T object, @Nullable T defaultValue); static boolean isEmpty(@Nullable String str);  }
@Test public void test_isEmpty() { assertThat(isEmpty(null)).isTrue(); assertThat(isEmpty("")).isTrue(); assertThat(isEmpty(" ")).isFalse(); assertThat(isEmpty("foo")).isFalse(); }