--- checkstyle-8.0/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheck.java	2021-05-11 07:12:44.130695340 +0200
+++ checkstyle-8.0/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheck.java	2021-05-11 07:12:56.534766508 +0200
@@ -216,7 +216,7 @@
     private boolean containsForbiddenFragment(String firstSentence) {
         String javadocText = JAVADOC_MULTILINE_TO_SINGLELINE_PATTERN
                 .matcher(firstSentence).replaceAll(" ");
-        javadocText = CharMatcher.WHITESPACE.trimAndCollapseFrom(javadocText, ' ');
+        javadocText = CharMatcher.whitespace().trimAndCollapseFrom(javadocText, ' ');
         return forbiddenSummaryFragments.matcher(javadocText).find();
     }
 }