diff --git a/Makefile b/Makefile
index 694122e6cc4f15a002197f08c76c1754579c1fe0..dcdf89f6902662e9a290a83772d246db0737dfc9 100644
--- a/Makefile
+++ b/Makefile
@@ -64,7 +64,7 @@ SLUBStoragePlugin.jar: $(OBJS)
 	@cd build; ${JAVAPATH}/jar cfvM ../$@ ./* ; cd ..
 
 %.class: %.java
-	${JAVAPATH}/javac -classpath ${CLASSPATH}:${JUNITCLASSPATH} -Xlint:all $< 
+	${JAVAPATH}/javac -classpath ${CLASSPATH}:${JUNITCLASSPATH} -Xlint:all -Werror $< 
 
 doc: $(SOURCES)
 	javadoc -d doc/ $^