Java 2 Platform, Enterprise Edition (J2EE), now known as Jakarta EE, is a platform developed by Sun Microsystems (now part of Oracle) for building robust, scalable, and distributed enterprise applications. J2EE provides a set of standardized APIs and tools for developers to create multi-tiered applications efficiently.

Core Features
1. Component-Based Architecture: Supports reusable components like servlets, Enterprise JavaBeans (EJB), and JavaServer Pages (JSP).
2. Platform Independence: Write applications once and run them anywhere with Java Virtual Machine (JVM) support.
3. Scalability: Handles high user loads by supporting clustering and distributed systems.
4. Security: Offers APIs for authentication, authorization, and secure communication.
5. Integration: Supports integration with various enterprise technologies like databases, messaging systems, and web services.

Key Technologies
- Servlets: Java classes that handle HTTP requests and responses.
- EJB: Business logic components for managing transactions and session handling.
- JSP: Simplifies web development by embedding Java code in HTML.
- JDBC: Facilitates database interaction.

Use Cases
- Developing e-commerce platforms, customer relationship management (CRM) systems, and supply chain management software.
- Building applications requiring robust transaction handling and distributed processing.

J2EE's extensive ecosystem and support for enterprise-grade applications have made it a cornerstone for businesses worldwide.