Customizing serialization/deserialization with lambda expressions in Java

13 Oct 2023

Serialization and deserialization are important concepts in Java when it comes to persisting and transmitting objects. By default, Java provides a standard mechanism for serializing and deserializing objects. However, there may be cases where you need to customize this process to suit your specific requirements.

Lambda expressions, introduced in Java 8, provide a concise way to implement functional interfaces. They can also be used to customize serialization and deserialization operations. In this article, we will explore how lambda expressions can be leveraged to achieve custom serialization and deserialization in Java.

Serialization

When an object is serialized in Java, its state is converted into a sequence of bytes that can be stored or transmitted. By default, Java uses the fields of the object to perform the serialization process. However, you can customize this behavior with lambda expressions.

To customize serialization, you need to implement the Serializable interface and define a lambda expression for the writeObject() method. This method allows you to define how the object should be serialized. Here’s an example:

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class CustomSerializableObject implements Serializable {
    private String message;

    public CustomSerializableObject(String message) {
        this.message = message;
    }

    private void writeObject(ObjectOutputStream out) throws IOException {
        out.writeUTF(message.toUpperCase()); // Custom serialization logic
    }
}

In this example, the writeObject() method is overridden to convert the message field to uppercase before serialization. This means that when an instance of CustomSerializableObject is serialized, the value of message will be stored in uppercase.

Deserialization

Deserialization is the opposite process of serialization, where the byte sequence is converted back into an object. To customize deserialization, you need to define a lambda expression for the readObject() method of the Serializable interface.

Here’s an example that demonstrates how to customize deserialization using lambda expressions:

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;

public class CustomDeserializableObject implements Serializable {
    private String message;

    public CustomDeserializableObject(String message) {
        this.message = message;
    }

    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
        message = in.readUTF().toLowerCase(); // Custom deserialization logic
    }
}

In this example, the readObject() method is overridden to convert the deserialized value of message to lowercase. This means that when an instance of CustomDeserializableObject is deserialized, the value of message will be stored in lowercase.

Conclusion

Lambda expressions provide a powerful way to customize serialization and deserialization operations in Java. By implementing the appropriate methods from the Serializable interface, you can define custom serialization and deserialization logic for your objects. This allows you to finely control how objects are stored, transmitted, and recreated from byte sequences.

Customizing serialization and deserialization with lambda expressions gives you greater flexibility and control over the serialization process. It enables you to handle specific concerns, such as data transformation or encryption, during the serialization and deserialization operations.

By leveraging the power of lambda expressions, you can make your Java applications more robust and adaptable when it comes to object persistence and transmission.

References

Java Documentation: Serializable