Java application servers are critical components in deploying and managing Java-based applications, especially for enterprise-level applications. Different application servers come with distinct features, performance characteristics, and support for Java EE (Jakarta EE) technologies. In this comparison, we’ll explore the main differences between three popular Java application servers: Tomcat, WildFly, and GlassFish.
1. Overview of Tomcat, WildFly, and GlassFish
- Apache Tomcat:
- Type: Servlet container (Web server).
- Primary Role: Handles HTTP requests, processes Java Servlets, and serves JavaServer Pages (JSP).
- Focus: Lightweight, highly scalable web server and servlet container for web applications.
- Java EE/Jakarta EE Support: Partial (Servlet, JSP, EL, WebSocket).
- WildFly (formerly JBoss AS):
- Type: Full Java EE (Jakarta EE) application server.
- Primary Role: Complete application server with support for EJB, JPA, JAX-RS, JMS, and more.
- Focus: Full-fledged support for enterprise Java applications, with modern features and good performance.
- Java EE/Jakarta EE Support: Full (including EJB, JPA, JMS, CDI, etc.).
- GlassFish:
- Type: Full Java EE (Jakarta EE) reference implementation.
- Primary Role: The reference implementation of Java EE, now Jakarta EE.
- Focus: Comprehensive support for Java EE technologies, especially for developers looking for a standards-compliant Java EE server.
- Java EE/Jakarta EE Support: Full (including EJB, JPA, JMS, CDI, etc.).
2. Core Features Comparison
| Feature | Tomcat | WildFly | GlassFish |
|---|---|---|---|
| Type of Server | Servlet container (Web server) | Full Java EE (Jakarta EE) server | Full Java EE (Jakarta EE) server |
| Java EE/Jakarta EE Support | Partial (Servlet, JSP, EL) | Full (JPA, EJB, JMS, CDI, JAX-RS) | Full (JPA, EJB, JMS, CDI, JAX-RS) |
| Deployment | WAR files only | EAR, WAR, and other deployments | EAR, WAR, and other deployments |
| WebSocket Support | Yes (Servlet 3.0+) | Yes (Java EE 7+) | Yes (Java EE 7+) |
| Clustering/Load Balancing | Limited (with third-party tools) | Supported (Native clustering) | Supported (Native clustering) |
| Management Console | No (CLI and XML configurations) | Yes (Web Console and CLI) | Yes (Admin Console) |
| Performance | High performance for web apps | High performance for enterprise apps | Good performance, especially for EE apps |
| Microservices Support | Limited (Servlet-based) | Strong (with Undertow and WildFly Swarm for microservices) | Moderate (but possible) |
| Transaction Management | Not supported | Full support (JTA, XA transactions) | Full support (JTA, XA transactions) |
| Enterprise Integration | Limited | Full support (JMS, JCA, Web Services) | Full support (JMS, JCA, Web Services) |
3. Deployment Models
- Tomcat:
- Deployment Format: Primarily supports WAR (Web Application Archive) files. It’s designed to serve only web applications that use servlets and JSPs.
- Notable Limitation: Tomcat does not support Enterprise JavaBeans (EJBs), Java Message Service (JMS), or Java Persistence API (JPA) out-of-the-box. Thus, it’s more suitable for simple web applications rather than complex enterprise applications.
- WildFly:
- Deployment Format: Supports EAR (Enterprise Application Archive), WAR, and other deployment formats. WildFly is a full Java EE server that supports a wide range of enterprise technologies.
- Notable Strength: Full support for EJB, JPA, JMS, CDI, and Web Services, making it suitable for large-scale enterprise applications.
- GlassFish:
- Deployment Format: Supports EAR, WAR, and EJB-based applications. It is the reference implementation for Java EE, and fully supports all standard Java EE technologies.
- Notable Strength: Since it’s the reference implementation, it often leads in adopting new features and changes to Jakarta EE standards.
4. Performance and Scalability
- Tomcat:
- Since Tomcat is lightweight, it generally performs very well for web applications and has low overhead. However, it’s less suitable for enterprise-level applications that require full Java EE capabilities.
- Scalability: Good for small to medium-sized web applications but requires external solutions for things like clustering and distributed transactions.
- WildFly:
- Known for its high performance and scalability for enterprise applications. WildFly also has undertow as its core web server, which is fast and lightweight.
- Scalability: Strong support for clustering and load balancing, making it well-suited for large-scale, highly distributed applications.
- GlassFish:
- GlassFish provides good performance and is a complete application server with full support for Jakarta EE. It might not be as performant as WildFly in some cases, but it is still highly capable.
- Scalability: Offers clustering and load balancing support, similar to WildFly. However, its performance is often seen as slightly behind WildFly for complex enterprise applications.
5. Management and Monitoring
- Tomcat:
- Management: Tomcat does not have a built-in GUI console. Management is done via configuration files (such as
server.xmlandweb.xml) and CLI commands. - Monitoring: You can use tools like JMX or third-party solutions like Apache Tomcat Manager for monitoring.
- Management: Tomcat does not have a built-in GUI console. Management is done via configuration files (such as
- WildFly:
- Management Console: WildFly has a web-based management console and a CLI for configuration and monitoring.
- Monitoring: Supports JMX, Prometheus, and other monitoring tools. WildFly also integrates well with enterprise monitoring tools like JBoss Operations Network.
- GlassFish:
- Management Console: GlassFish provides a web-based admin console that allows for easy management and configuration.
- Monitoring: It supports JMX, and SNMP, and integrates with tools like Prometheus and Grafana for monitoring.
6. Community and Support
- Tomcat:
- Community: As an Apache project, Tomcat has a large community and lots of resources available for support, documentation, and troubleshooting.
- Support: Commercial support is available through vendors like VMware, but community support is the primary option for open-source users.
- WildFly:
- Community: WildFly is backed by Red Hat, with a strong and active community contributing to the development of the server.
- Support: Red Hat offers commercial support through Red Hat JBoss Enterprise Application Platform (EAP).
- GlassFish:
- Community: Originally developed by Oracle, GlassFish now has a community-driven development model under the Eclipse Foundation.
- Support: Commercial support is available through Oracle or consulting firms, but community support can sometimes be limited compared to WildFly.
7. Use Case Recommendations
- Tomcat:
- Best suited for simple web applications that don’t require full Java EE features.
- Suitable for smaller projects, microservices, and applications where you need fast startup time and scalability with minimal overhead.
- WildFly:
- Ideal for enterprise-level applications that require the full range of Java EE capabilities, including EJBs, JMS, and JPA.
- Excellent for applications needing high scalability and robust support for distributed systems, especially in microservices.
- GlassFish:
- Best for developers looking for a reference implementation of Java EE or Jakarta EE.
- Suitable for applications that require full Java EE support and standards compliance.
- Good for testing and development environments where using the reference implementation of Jakarta EE is important.