StringUtils { public static boolean isNotEmpty(@Nullable String string) { return string != null && !string.isEmpty(); }  static boolean isNotEmpty(@Nullable String string);  }
@Test public void testString() { assertThat(StringUtils.isNotEmpty("bla")).isEqualTo(true); }
@Test public void testEmptyString() { assertThat(StringUtils.isNotEmpty("")).isEqualTo(false); }
@Test public void testNull() { assertThat(StringUtils.isNotEmpty(null)).isEqualTo(false); }