src/share/classes/sun/awt/FontConfiguration.java

@@ -2107,10 +2107,11 @@
                 return map.get(key);
             }
             return ret;
         }
 
+        @SuppressWarnings("serial") // JDK-implementation class
         class FontProperties extends Properties {
             public synchronized Object put(Object k, Object v) {
                 parseProperty((String)k, (String)v);
                 return null;
             }