StringUtils { public static boolean isEmpty(final String value) { return value == null || BLANK.equals(value); }  @Deprecated static String concatWithSpace(final String... styles); static boolean isEmpty(final String value); static boolean isNotEmpty(final String value); static String getNotNullValue(final String value, final String alternative); static String getNullSafeValue(final String value); @Deprecated static String joinWithCommaSeparator(final Collection<String> values); @Deprecated static String joinWithCommaSeparator(final Collection<String> values, boolean escape); @Deprecated static String joinWithSpaceSeparator(final Collection<String> values); static final String BLANK; static final String SPACE; static final String SEPARATOR_COMMA; }
@Test void testIsEmpty() { assertThat(StringUtils.isEmpty(null)).isTrue(); assertThat(StringUtils.isEmpty("")).isTrue(); assertThat(StringUtils.isEmpty(" ")).isFalse(); assertThat(StringUtils.isEmpty("foo")).isFalse(); }