Interface Externalizable

Interface java.io.Externalizable

Interface Members | This Package | All Packages

public interface Externalizable
extends Serializable

Externalization allows a class to specify the methods to be used to write the object's contents to a stream and to read them back. The Externalizable interface's writeExternal and readExternal methods are implemented by a class to give the class complete control over the format and contents of the stream for an object and its supertypes. These methods must explicitly coordinate with the supertype to save its state.
Object Serialization uses the Serializable and Externalizable interfaces. Object persistence mechanisms may use them also. Each object to be stored is tested for the Externalizable interface. If the object supports it, the writeExternal method is called. If the object does not support Externalizable and does implement Serializable the object should be saved using ObjectOutputStream.
When an Externalizable object is to be reconstructed, an instance is created using the public no-arg constructor and the readExternal method called. Serializable objects are restored by reading them from an ObjectInputStream.

See Also:
ObjectOutputStream, ObjectInputStream, ObjectOutput, ObjectInput, Serializable