Code Correctness: readObject() Invokes Overridable Function

The readObject() method within the class calls a function that may be overridden.

During deserialization, readObject() acts like a constructor, so object initialization is not complete until this function ends. Therefore when a readObject() function of a Serializable class calls an overridable function, this may provide the overriding method access to the object's state prior to it being fully initialized.

Example 1: The following readObject() function calls a method that can be overridden.

  ...
  private void readObject(final ObjectInputStream ois) throws IOException, ClassNotFoundException {
    checkStream(ois);
    ois.defaultReadObject();
  }

  public void checkStream(ObjectInputStream stream){
    ...
  }

Since the function checkStream() and its enclosing class are not final and public, it means that the function can be overridden, which may mean that an attacker may override the checkStream() function in order to get access to the object during deserialization.