🚀 J2EE-Example-Project

📝 Project Overview

J2EE-Example-Project is a modular Java EE application designed to demonstrate best practices in enterprise application development. This project covers user authentication, product management, email verification, and secure role-based access control using EJBs, servlets, JSP, Jakarta EE Security API, and Hibernate ORM. The architecture is layered and scalable, making it ideal for learning and extending real-world enterprise Java solutions.

🗂️ Project Structure

J2EE-Example-Project/
├── auth/
│   └── src/main/java/lk.jiat.app.ejb.bean/
│       └── UserSessionBean.java
├── core/
│   └── src/main/java/lk.jiat.app.core/
│       ├── exception/
│       │   ├── InvalidParameterException.java
│       │   └── LoginFailedException.java
│       ├── mail/
│       │   ├── Mailable.java
│       │   └── VerificationMail.java
│       ├── model/
│       │   ├── Product.java
│       │   ├── Status.java
│       │   ├── User.java
│       │   └── UserType.java
│       ├── provider/
│       │   └── MailServiceProvider.java
│       ├── service/
│       │   ├── ProductService.java
│       │   └── UserService.java
│       └── util/
│           ├── Encryption.java
│           └── Env.java
│       └── resources/
│           ├── META-INF/persistence.xml
│           └── application.properties
├── product/
│   └── src/main/java/lk.jiat.app.ejb.bean/
│       └── ProductSessionBean.java
├── web/
│   └── src/main/java/lk.jiat.app.web/
│       ├── listener/
│       │   └── ContextListener.java
│       ├── security/
│       │   ├── AppIdentityStore.java
│       │   └── AuthMechanism.java
│       └── servlet/
│           ├── AddProduct.java
│           ├── deleteProduct.java
│           ├── Login.java
│           ├── Logout.java
│           ├── Register.java
│           ├── Test.java
│           └── VerifyEmail.java
│   └── src/main/webapp/
│       ├── admin/
│       │   ├── add_product.jsp
│       │   └── index.jsp
│       ├── user/
│       │   └── index.jsp
│       ├── WEB-INF/
│       │   └── web.xml
│       ├── 500.jsp
│       ├── index.jsp
│       ├── login.jsp
│       ├── login_error.jsp
│       ├── register.jsp
│       └── unauthorized.jsp
├── ear/
│   └── src/main/
│       ├── java/
│       └── resources/
├── pom.xml

📦 Module Details

🟦 auth (EJB Module)

• UserSessionBean.java
  Stateless EJB for user management: registration, authentication, update, and deletion. Integrates with the core model and service interfaces.

🟦 core (Core Business Logic)

• exception/
  Custom exceptions for parameter validation and login failures.

• mail/
  Email sending logic, including verification emails for user registration.

• model/
  JPA entities for User, Product, and supporting enums for status and user type.

• provider/
  Singleton mail service provider for asynchronous email delivery.

• service/
  Remote interfaces for user and product business logic.

• util/
  Utility classes for password encryption and environment variable management.

• resources/
  JPA persistence configuration and application properties.

🟦 product (EJB Module)

• ProductSessionBean.java
  Stateless EJB for product CRUD operations, category filtering, and business logic.

🟦 web (Web Layer)

• listener/ContextListener.java
  Initializes and shuts down the mail service provider.

• security/
  Implements Jakarta EE Security API for authentication and identity management.

• servlet/
  Servlets for login, logout, registration, product management, email verification, and testing.

• webapp/
  JSP pages for admin and user dashboards, login, registration, error handling, and unauthorized access.

• WEB-INF/web.xml
  Security constraints, role mappings, and error page configuration.

🟦 ear (Enterprise Archive)

• Assembles all modules (auth, product, core, web) into a deployable EAR for enterprise servers.

⚙️ Key Features

• ✅ Modular Maven multi-module structure (EJB, web, core, EAR)
• ✅ User registration with email verification
• ✅ Secure login/logout and session management
• ✅ Role-based access control (SUPER_ADMIN, ADMIN, USER)
• ✅ Product management (CRUD, category filtering)
• ✅ Custom exception handling and error pages
• ✅ Asynchronous email sending for verification
• ✅ Password encryption for secure storage
• ✅ Clean separation of concerns and layered architecture

💡 How It Works

• User Registration:
  Users register via a form; their data is persisted and a verification email is sent. Upon clicking the verification link, their account is activated.

• Authentication & Authorization:
  Login is handled via a servlet and Jakarta EE Security API. Roles are assigned and enforced at both servlet and EJB levels.

• Product Management:
  Admins can add, view, and delete products via JSP pages and servlets. Products are managed using EJBs and JPA.

• Session & Error Handling:
  Secure session management ensures users can log out safely. Custom error pages handle login failures, unauthorized access, and server errors.

• Email Service:
  The mail provider uses a thread pool for efficient, non-blocking email delivery, supporting verification and notification workflows.

🛠️ Technologies Used

• Java 11
• Jakarta EE 10 (EJB, Servlet, JPA, Security)
• Hibernate ORM
• JSP & JSTL
• Maven
• MySQL (for persistence)
• Jakarta Mail

📚 Learning Outcomes

• ✅ Build modular, maintainable Java EE applications
• ✅ Implement secure authentication and role-based authorization
• ✅ Integrate EJBs, servlets, and JSP in a real-world project
• ✅ Use JPA/Hibernate for ORM and database management
• ✅ Apply best practices for error handling and email verification

🧑‍💻 Author

Chamika Gayashan
Undergraduate Software Engineer | Sri Lanka
Linkedin: @chamikathereal
Current date: Saturday, July 05, 2025, 12:48 AM +0530