why is serialization used in java code example

Example 1: serialization of object in java

Serialization in Java is a mechanism of writing 
the state of an object into a byte-stream. 
It is mainly used in Hibernate, RMI, JPA, EJB and JMS technologies.

Example 2: what is serialization in java

Serialization; when we MAP a Java object to API JSON
format (CONVERT JAVA OBJECT TO JSON);

Deserialization; API JSON/XML ^ MAP it to Java Object
(JSON TO JAVA OBJECT)