A DESCRIPTION OF THE PROBLEM :
Near the top of the Javadoc for the java.io.Serializable interface, the following paragraph is written:
 Classes that require special handling during the serialization and deserialization process must implement special methods with these exact signatures:

 private void writeObject(java.io.ObjectOutputStream out)
     throws IOException
 private void readObject(java.io.ObjectInputStream in)
     throws IOException, ClassNotFoundException;
 private void readObjectNoData()
     throws ObjectStreamException;
 
Note that the first abstract method declaration does not have a semicolon at the end, while the other two have a semicolon at the end.