diff --git a/config/pmd.xml b/config/pmd.xml
index f26f4755b..fc0e00772 100644
--- a/config/pmd.xml
+++ b/config/pmd.xml
@@ -115,7 +115,6 @@
     <exclude name="ImmutableField"/>
     <!-- this rule does not have any option, unreasonable to use -->
     <exclude name="MissingBreakInSwitch"/>
-    <exclude name="AbstractClassWithoutAbstractMethod"/>
     <exclude name="SimplifyConditional"/>
     <exclude name="CompareObjectsWithEquals"/>
     <exclude name="PositionLiteralsFirstInComparisons"/>
diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/checks/DeclarationCollector.java b/src/main/java/com/puppycrawl/tools/checkstyle/checks/DeclarationCollector.java
index df164529f..20ac6466b 100644
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/DeclarationCollector.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/DeclarationCollector.java
@@ -229,7 +229,7 @@ public abstract class DeclarationCollector extends Check
      * @author Stephen Bloch
      * June 19, 2003
      */
-    private abstract static class LexicalFrame
+    private static class LexicalFrame
     {
         /** Set of name of variables declared in this frame. */
         private final Set<String> varNames;