diff --git a/pmd/src/plugin-test/project.xml b/pmd/src/plugin-test/project.xml
index 7b5a2f93..d1db9e1f 100644
--- a/pmd/src/plugin-test/project.xml
+++ b/pmd/src/plugin-test/project.xml
@@ -18,7 +18,7 @@
  -->
 
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0">
   <pomVersion>3</pomVersion>
   <id>test-maven-pmd-plugin</id>
   <name>Test project for Maven PMD Plugin</name>