What is the difference between Serializable and Externalizable in Java?

Question

What is the difference between Serializable and Externalizable in Java?

Answer 1

Basically, Serializable is a marker interface that implies that a class is safe for serialization and the JVM determines how it is serialized. Externalizable contains 2 methods, readExternal and writeExternal. Externalizable allows the implementer to decide how an object is serialized, where as Serializable serializes objects the default way.