Merge branch 'pr-576'

docs/pages/release_notes.md

@@ -232,3 +232,5 @@ All existing rules have been updated to reflect these changes. If you have custo
 *   [#557](https://github.com/pmd/pmd/pull/557): \[java] Fix NPath metric not counting ternaries correctly - [Clément Fournier](https://github.com/oowekyala)
 *   [#563](https://github.com/pmd/pmd/pull/563): \[java] Add support for basic method type inference for strict invocation - [Bendegúz Nagy](https://github.com/WinterGrascph)
 *   [#567](https://github.com/pmd/pmd/pull/567): \[java] Last API change for metrics (metric options) - [Clément Fournier](https://github.com/oowekyala)
+*   [#576](https://github.com/pmd/pmd/pull/576): \[doc][java] Add hint for Guava users in InefficientEmptyStringCheck - [mmoehring](https://github.com/mmoehring)
+

pmd-java/src/main/resources/rulesets/java/strings.xml

@@ -221,8 +221,9 @@ if (s.indexOf('d') {}
 String.trim().length() is an inefficient way to check if a String is really empty, as it
 creates a new String object just to check its size. Consider creating a static function that
 loops through a string, checking Character.isWhitespace() on each character and returning
-false if a non-whitespace character is found. You can refer to Apache's StringUtils#isBlank (in commons-lang)
-or Spring's StringUtils#hasText (in the Springs framework) for existing implementations.
+false if a non-whitespace character is found. You can refer to Apache's StringUtils#isBlank (in commons-lang),
+Spring's StringUtils#hasText (in the Spring framework) or Google's CharMatcher#whitespace (in Guava) for
+existing implementations.
     </description>
     <priority>3</priority>
     <example>