Object Serialization

• ObjectInputStream and ObjectOutputStream allows you to read and write objects from any class (not just primitive types).

• Java objects are serialized with writeObject() and deserialized with readObject(). For example:

  • Vector lines = new Vector( 256 ); ...
  • try {
  • new ObjectOutputStream(
  • new GZIPOutputStream(
  • new FileOutputStream( filename ) ) );
  • out.writeObject( lines );
  • out.close();
  • } catch ( IOException e ) { }

• Only objects of classes that implement Serializable (or Externalizable) can be serialized. (The Serializable interface defines no methods.)

• Object variables not to be serialized are called transient.

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