diff --git a/maven/core-unittests/pmd.xml b/maven/core-unittests/pmd.xml
index b261165849..3cebb7cb9f 100644
--- a/maven/core-unittests/pmd.xml
+++ b/maven/core-unittests/pmd.xml
@@ -6,5 +6,6 @@
     <description>PMD rules for core unit tests.</description>
     <rule ref="rulesets/java/quickstart.xml">
         <exclude name="UselessParentheses"/>
+        <exclude name="ReturnEmptyCollectionRatherThanNull"/>
     </rule>
 </ruleset>