Where is serialization used

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The main class implementation of is showed in the next code. Only objects that support the java. Serializable interface can be written to streams. In this example, we are going to serialize the object of Student class from above code. The writeObject method of ObjectOutputStream class provides the functionality to serialize the object.

We are saving the state of the object in the file named f. Deserialization is the process of reconstructing the object from the serialized state. It is the reverse operation of serialization.

Let's see an example where we are reading the data from a deserialized object. If a class implements Serializable interface then all its sub classes will also be serializable. Let's see the example given below:. Parent class properties are inherited to subclasses so if parent class is Serializable, subclass would also be.

If a class has a reference to another class, all the references must be Serializable otherwise serialization process will not be performed. In such case, NotSerializableException is thrown at runtime.

If there is any static data member in a class, it will not be serialized because static is the part of class not object. Rule: In case of array or collection, all the objects of array or collection must be serializable. If any object is not serialiizable, serialization will be failed. The Externalizable interface provides the facility of writing the state of an object into a byte stream in compress format. It is not a marker interface. Now, id will not be serialized, so when you deserialize the object after serialization, you will not get the value of id.

It will return default value always. In such case, it will return 0 because the data type of id is an integer. The serialization process at runtime associates an id with each Serializable class which is known as SerialVersionUID.