Emergency! Writing an object into a file (NotSerializableException)

Question

Hi, I am now working in a project. I came across a serialization problem which I am spending so many days and haven't gotten any solution.
I assume that the problem is caused by the complexity of class design in a package. The saved object extends all of 9~11 classes in which some are abstract class, some are listening interface class, some are just normal class but extending from GUI components such as JTree, JFrame and so on. Besides static is spred over anywhere in the classes.
code:(No problem here)
output = new ObjectOutputStream( new eFileOutputStream( fileName ) );
output.writeObject(prj);
output.flush();
Futher, the 'prj' object is proved to be very serializable as a result of "isSerializable()" function before writting in to a file. However it invokes IOExceptions, isn't it funny?
ex:
A--B--C--D--E
|
|
F G H
| |
I J
|
prj
In the example of above, is it possible to store all the state of objects A to J by storing prj so that I can re-construct the whole of objects relations and the members in them from the stored 'prj'?
Back to the original problem, then...
Do I have to get rid of all the static declarations of parent classes?
Do I have to serialize each single classes one by one without being greedy tryint to store all of the state of objects linked to 'prj' at once?
Do I have to get every single objects implemented 'Serializable' including abstruct and interface classes if they contains static declaration or someting unserializable?
Please give me any help or hint, anything I am appreciate for.

Answer 1

The problem is not very clear. Some code snippets might help. Especially the Exception details.Your object graph is somewhat confusing too.
To answer your questions, the default Serialization (where the object prj, though extends java.io.Serializable, DOESN'T implement writeObject() and readObject() methods) will succeed only if all the reachable super classes in the graph are a. either implement Serializable or b. have no-argument constructors. In case of b., it's the responsibility of the object prj to re-establish the state of the parent classes from the serialized stream. You can do that by implementing writeObject() and readObject() methods themselves.
The transient and static fields are never serialized. So if you want to preserve the value of a static field then you'll have to either a. explicitly serialize that field out to the ObjectOutputStream and read it back from the ObjectInputStream in the writeObject() and readObject() methods or b. using reflection where you can get the Class name and get the static field value from the corresponding 'Class' data type also using reflection (object.getClass().getField("fieldName").getValue(null)).