It is a process of reconstructing an object from the serialized state.it is also called reverse operation.
If the class implement serialization then all the sub-classes will be serializable.
If the class has a reference to another class, all references must be serializable or the serialization process will never be performed. In that case at runtime, NotSerializableException gets thrown.
Serializable is known as marker Interface, it is used for “mark” java classes so the object of those classes may get a certain capability. The remote & cloneable are also marker interfaces.
It should be implemented by the class whose object you want to persist.
By default, the whole wrapper classes & string class implement the java.io.serializable interface.
With collection or array. all objects of the array or collection should be serializable. If the object not serializable then it will be failed.