private static Object getObject(Writable writable, Holder<Integer> size) {
   Class<?> writableClass = NullWritable.class;
   if (writable != null) {
     writableClass = writable.getClass();
   }
   HdfsWritableFactories.HdfsWritableFactory writableObjectFactory =
       WritableCache.readables.get(writableClass);
   return writableObjectFactory.read(writable, size);
 }
 private static Writable getWritable(
     Object obj, TypeConverter typeConverter, Holder<Integer> size) {
   Class<?> objCls = obj == null ? null : obj.getClass();
   HdfsWritableFactories.HdfsWritableFactory objWritableFactory =
       WritableCache.writables.get(objCls);
   if (objWritableFactory == null) {
     objWritableFactory = new HdfsWritableFactories.HdfsObjectWritableFactory();
   }
   return objWritableFactory.create(obj, typeConverter, size);
 }