Serializing swing/awt components

Question

I am trying to serialize a JPanel but everytime i get this error:

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: javax.swing.GroupLayout  

Can you tell me, what could be the problem or what is the proper way of serializing it.

What i do is pretty simple:

FOR Serializing:

FileOutputStream f = new FileOutputStream("myfile.dat");
ObjectOutputStream ostream = new ObjectOutputStream(f);
Object object = panel;  //where panel is a JPanel type object
ostream.writeObject(object);
ostream.close();

And now for deserializing:

File file = new File("myfile.dat");
ObjectInputStream in;
try {
   in = new ObjectInputStream(new FileInputStream(file));
   object = (JPanel) in.readObject();
   in.close();
} catch (Exception e2) {
   e2.printStackTrace();
}  

while reading the serialized object in last step i encounter the above error. What is the reason, or any idea how is should do this?

Answer 1

JPanel implements Serializable...

But javax.swing.GroupLayout don't.

So, you need to change GroupLayout to another layout class!

Answer 2

GroupLayout , which appears to have been added to the panel, is not serialisable. There are a few options (listed least to most favourable).

• Subclass GroupLayout to create a serial proxy (see Effective Java 2nd Ed). This is a fair bit of work, and is complicated by GroupLayout not having a complete set of "getters and setters".

• Replace GroupLayout with a serialisable LayoutManager . There's the functional but rough GridBagLayout in the Java library. Other layout managers are available.

• Don't serialise the JPanel . Making AWT components serialisable (and the whole JavaBeans thing) was a laughable mistake.

Answer 3

To be serializeable the object (and all the parts of it with exception of the POJOs) needs to implement the Serializable interface.

If you cannot change the class, take a look at XStream .

Answer 4

To serialize an object, all the objects it references need to also be serializable aswell. You can mark a reference transient if you don't want it to be serialized. This means, if your panel refers to objects which are not serilizable, make them serilizable aswell or mark them transient