src/share/classes/com/sun/imageio/plugins/jpeg/JFIFMarkerSegment.java

@@ -556,10 +556,11 @@
         }
     }
 
     // Could put reason codes in here to be parsed in writeJFXXSegment
     // in order to provide more meaningful warnings.
+    @SuppressWarnings("serial") // JDK-implementation class
     private class IllegalThumbException extends Exception {}
 
     /**
      * Writes out a new JFXX extension segment, without saving it.
      */