POJO (Plain Old Java Object), (usually used to represent data) 
The POJO Class usually have encapsulated fields :  
optionally constructors , toString
Serialization: POJO to JSON (or string, byte array) 
when we MAP a Java object to API JSON format (Java to JSON)
Car car = new Car(); car.setMake(“Toyota”); 
car.setModel(“Camry”); given().body(car).when().post(uri)
De-Serialization: 
JSON to POJO ( API JSON/XML → MAP it to Java Object (JSON TO JAVAOBJECT)
Car car2 = new Car(); car2=when().get(uri).body.as(car.class); 
car.setMake(“Toyota”); car.setModel(“Camry”);