20.7. Custom Serialization with Externalizable

Try these first

1. 1.

   What is the main purpose of the Externalizable interface?

   Hint

   Think about how serialization differs between Externalizable and Serializable.

2. 2.

   Name the two methods you must implement when using Externalizable.

   Hint

   Consider what you need to do for serialization and deserialization.

3. 3.

   What must a class implement to allow custom serialization?

   • Serializable
   • Externalizable
   • Cloneable

   Hint

   Think about which interface provides more control.

4. 4.

   True or False: Using Externalizable, all fields in a class must be serialized.

   • True
   • False

   Hint

   Consider why you might want to skip fields.

5. 5.

   Design a custom object in Java that implements Externalizable. Explain how your choice of fields impacts serialization performance.

   Hint

   Contemplate the size and sensitivity of data.

6. 6.

   Discuss how you would handle versioning issues when using Externalizable across different versions of an application.

   Hint

   Think about maintaining backward compatibility.