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

*** 2107,2116 ****
--- 2107,2117 ----
                  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;
              }