diff --git a/java/org/slub/rosetta/dps/repository/plugin/SLUBXmlFormatValidationPlugin.java b/java/org/slub/rosetta/dps/repository/plugin/SLUBXmlFormatValidationPlugin.java
index fd3e46c87228012b4a8865614c65d6474182e0c6..a53ed065c1bc85f19647e4a25618eff256e2c355 100644
--- a/java/org/slub/rosetta/dps/repository/plugin/SLUBXmlFormatValidationPlugin.java
+++ b/java/org/slub/rosetta/dps/repository/plugin/SLUBXmlFormatValidationPlugin.java
@@ -375,9 +375,10 @@ public class SLUBXmlFormatValidationPlugin implements FormatValidationPlugin {
     private ValidationSchemaType checkIfDtdIsApplicable(Document doc) {
         ValidationSchemaType result = ValidationSchemaType.nothing;
         var info = getXMLinfo(doc);
-        if (null != info.systemID && info.systemID.endsWith(".dtd")) {
-            result = ValidationSchemaType.dtd;
-        } else if (null != info.systemID) {
+        if (null != info.systemID) {
+            if (info.systemID.endsWith(".dtd")) {
+                result = ValidationSchemaType.dtd;
+            }
             if (debug) {
                 System.out.println("no dtd applicable");
             }