What is the difference between serialization and externalization?

Externalization provides implementation logic control to the application by overriding readExternal and writeExternal methods. In serializable interface uses reflection which causes relatively slow performance. Externalizable gives full control over the implementation approach.

What is serializable and Externalizable?

A serializable interface is used to implement serialization. An externalizable interface used to implement Externalization. Serializable is a marker interface i.e. it does not contain any method. The externalizable interface is not a marker interface and thus it defines two methods writeExternal() and readExternal().

What is the difference between serialization and Deserialization?

Serialization is a mechanism of converting the state of an object into a byte stream. Deserialization is the reverse process where the byte stream is used to recreate the actual Java object in memory. So, the object serialized on one platform can be deserialized on a different platform.

What is the use of serialization ID in Java?

The serialization at runtime associates with each serializable class a version number called a serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization.

What is Externalizable?

Externalizable is an interface that enables you to define custom rules and your own mechanism for serialization. Thus externalization comes to give the programmers full control in reading and writing objects during serialization . As name suggest it is externalilizing your serialization.

Why is serialization required?

Well, serialization allows us to convert the state of an object into a byte stream, which then can be saved into a file on the local disk or sent over the network to any other machine. And deserialization allows us to reverse the process, which means reconverting the serialized byte stream to an object again.

What is the advantage of serialization in Java?

Serialization allows us to transfer objects through a network by converting it into a byte stream. It also helps in preserving the state of the object. Deserialization requires less time to create an object than an actual object created from a class. hence serialization saves time.

and give a sample code.. Serialization is a mechanism of writing the state of object into a byte stream.The String class and all wrapper classes implements Serializable interface bydefault. Externalization is a mechanism of writing the state of object into a byte stream in compress format.

Which is better serializable or externalizable interface in Java?

The externalizable interface provides all serialization responsibilities to a programmer and hence JVM has no control over serialization. Serialization using a serializable interface has bad performance. Serialization using an externalizable interface has better performance.

How does serialization extend the life of an object?

The mechanism does not depend on the operating system, which means you can transfer objects via your network and restore them at the other side of the wire. With serialization, you can easily implement a so-called lightweight persistence, prolonging an object’s life beyond the life of the application.