[FIXED JENKINS-36717] - Enforce FindBugs in the Jenkins core build

core/pom.xml

@@ -42,8 +42,8 @@ THE SOFTWARE.
     <stapler.version>1.243</stapler.version>
     <spring.version>2.5.6.SEC03</spring.version>
     <groovy.version>2.4.7</groovy.version>
-    <!-- Currently there is a huge number of errors => we cannot fix all of them immediately -->
-    <findbugs.failOnError>false</findbugs.failOnError>
+    <!-- TODO: Actually many issues are being filtered by src/findbugs/findbugs-excludes.xml -->
+    <findbugs.failOnError>true</findbugs.failOnError>
   </properties>
 
   <dependencies>