Difference Between POJO and Model in Java & Spring Boot

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In Java and Spring Boot, POJO and Model are the terms of class that are commonly used, sometimes exchangeable. However, both are different to each other depending on the context and MVC (Model-View-Controller)architecture application development. This topic guides us about the difference between POJO and Model, their roles, and how they’re used in the real-world scenario.

Difference Between POJO and Model in Java & Spring Boot

POJO

A Plain Old Java Object is a simple and lightweight Java class with no rules for creating this class. It does not extend, implement, depend on any specific framework or API.

Key Characteristics of POJO

  • Contains only fields, constructors, getters, and setters.
  • Free of framework annotations (though can be used with them).
  • Used to represent structured data.

Example:

public class Product {
private String name;
private double price;
public Product() {}
public Product(String name, double price) {
this.name = name;
this.price = price;
 }
// Getters and Setters
}
  • POJOs are used universally in Java projects — for entities, DTOs, requests, etc.

What is a Model in Java and Spring Boot?

The term Model generally refers to the part of an application that represents the application’s data or domain layer. In Spring MVC, it’s used in web applications to pass data from the controller to the view.

Model as Domain Layer

In backend systems, a Model can mean the same as an entity or business object, which might be a POJO annotated with JPA or used in logic processing.

Model in Spring MVC

In the Spring MVC module the Model to bind Java objects to HTML templates such as Thymeleaf, JSP, etc..This Model is available in the package (org.springframework.ui.Model or ModelMap).

Model Class Example:

@Controller
public class ProductController {

@GetMapping("/product")
public String showProduct(Model model) {
Product product = new Product("Phone", 8000);
model.addAttribute("product", product);
return "productPage";
   }
}
  • Here, the Model is a container for sending POJOs (like Product) to the view layer.

Key Difference Between POJO and Model

FeaturePOJOModel (MVC/Domain Context)
DefinitionSimple Java objectThe object representing app data or controller-view bridge
AnnotationsTypically noneIt may be annotated  with this @Entity, @Component annotation.
Usage ContextAny layer (domain, request, DTO)Mainly in MVC pattern or business/domain layers
Framework DependencyNoYes (can be tied to Spring MVC or JPA)
Contains Logic?No (basic getters/setters)This may include validation, calculation, or logic
PurposeHold dataRepresent system state or transfer data to the view

When to Use POJO vs Model

Use POJO When

  • We need a plain object to structure data.
  • We are writing framework-independent logic.
  • We are building reusable components or APIs.

Use Model When

  • We are working in a Spring MVC Controller to pass data to a view.
  • We are building a domain layer for your application.
  • We are dealing with JPA Entities, View Models, or Web Models.
  • Real-World Example in Spring Boot MVC

Example of POJO Class

public class Product {
private String name;
private double price;
// Write Constructors, Getters, Setters
}

Example of Controller Using Model

@Controller
public class ProductController {

@GetMapping("/details")
public String productDetails(Model model) {
Product product = new Product("iPhone", 999.99);
model.addAttribute("product", product);
return "productDetails";
   }
}

In this flow:

  • In the above example the Product class is a POJO class. 
  • The model object is used to send the product object to the front-end view page.

Conclusion

POJO is a framework-agnostic data holder, used universally for entities, DTOs, helpers, and more.A  Model is a domain or business object (often a POJO with annotations). Or the Spring MVC Model class used to pass data to a view.

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