Introduction to Java EE: A beginner’s guide
Java Enterprise Edition (Java EE) is a powerful platform for developing enterprise-level web applications. Java EE provides a set of specifications and APIs that make it easy to build scalable, reliable, and secure applications. In this beginner’s guide, we will introduce you to Java EE and its key concepts.
What is Java EE?
Java Enterprise Edition (Java EE) is a platform that provides a set of specifications and APIs for building enterprise-level web applications. It is a set of technologies and services that make it easier to build large-scale, multi-tiered, scalable, and reliable web applications.
Java EE was originally called Java 2 Enterprise Edition (J2EE) but was renamed to Java EE in 2006. Java EE is built on top of the Java Standard Edition (Java SE) platform and adds enterprise-level features such as distributed computing, messaging, and web services.
Java EE is an open standard and is maintained by the Java Community Process (JCP), which is a group of companies and individuals who collaborate on developing the Java platform.
Key Concepts in Java EE
Here are some key concepts in Java EE that you should be familiar with:
- Component-based Development
Java EE is a component-based platform, which means that applications are built using reusable components. Components are self-contained modules that can be combined to create larger applications. Components can be either server-side or client-side and can be written in different programming languages.
Some examples of server-side components in Java EE are Servlets, JavaServer Pages (JSP), and Enterprise JavaBeans (EJB). These components are executed on the server-side and generate dynamic content that is sent to the client.
2. Multitier Architecture
Java EE applications are typically built using a multitier architecture, which separates the application into different layers. The three-tier architecture is the most common architecture used in Java EE applications. The three layers are:
- Presentation layer: This layer is responsible for handling the user interface and presenting data to the user. It includes components such as Servlets and JSPs.
- Business logic layer: This layer contains the business logic of the application and is responsible for processing data and performing operations. It includes components such as Enterprise JavaBeans (EJBs) and Java Persistence API (JPA).
- Data storage layer: This layer is responsible for storing and retrieving data. It includes components such as relational databases and the Java Database Connectivity (JDBC) API.
3. Containers
Java EE applications are executed in containers, which provide a runtime environment for the application. Containers provide services such as transaction management, security, and threading. There are two types of containers in Java EE:
- Web container: This container is responsible for executing web components such as Servlets and JSPs.
- EJB container: This container is responsible for executing Enterprise JavaBeans (EJBs).
4. API Specifications
Java EE provides a set of API specifications that define how components should be written and how they should interact with each other. The most common API specifications in Java EE are:
- Servlet API: This API is used to write web components such as Servlets and JSPs.
- Enterprise JavaBeans (EJB) API: This API is used to write business logic components such as EJBs.
- Java Persistence API (JPA): This API is used to interact with databases and perform data persistence operations.
- Java Message Service (JMS) API: This API is used to implement messaging between components in a Java EE application.
- Java Naming and Directory Interface (JNDI) API: This API is used to access naming and directory services in a Java EE application.
Java EE Application Servers
Java EE applications are typically deployed on application servers, which provide a runtime environment for the application. Application servers provide services such as transaction management, security, and resource management. There are several application servers available for Java EE, including:
- Apache Tomcat: Tomcat is a lightweight application server that is often used for small-scale applications.
- GlassFish: GlassFish is a full-featured application server that is built on top of the Java EE platform.
- WebLogic: WebLogic is an enterprise-level application server that is commonly used for large-scale applications.
- WildFly: WildFly is a fast, lightweight, and flexible application server that is designed for modern applications.
Getting Started with Java EE
To get started with Java EE, you will need to download and install an application server. Apache Tomcat and GlassFish are both free and open-source application servers that you can use to develop and test Java EE applications.
Once you have installed an application server, you can start developing Java EE applications using an Integrated Development Environment (IDE) such as Eclipse or IntelliJ IDEA. IDEs provide a set of tools and features that make it easy to develop, test, and debug Java EE applications.
When you start developing Java EE applications, you will need to become familiar with the different components and APIs that are available. You can start with the basic components such as Servlets and JSPs and then move on to more advanced components such as EJBs and JPA.
Conclusion
Java Enterprise Edition (Java EE) is a powerful platform for building enterprise-level web applications. Java EE provides a set of specifications and APIs that make it easy to build scalable, reliable, and secure applications. Java EE is a component-based platform that uses a multitier architecture and provides containers for executing applications. Java EE applications are typically deployed on application servers, which provide a runtime environment for the application.
In this beginner’s guide, we introduced you to Java EE and its key concepts. We hope that this guide has helped you understand the basics of Java EE and has encouraged you to start developing Java EE applications. With the right tools and knowledge, you can create powerful and scalable web applications using Java EE.
