Java application servers are available in a wide range of options, tailored to different needs. Building a simple e-commerce web app? Go with something lightweight like Apache Tomcat. Creating something more ambitious like an electronic health record system? Opt for an enterprise-ready solution like IBM WebSphere. There are solutions for both solo developers and Fortune 500 companies, as well as everyone in between.
What is a Java Application Server?
A Java application server is a runtime platform for Java web applications, providing services such as transaction management, security, concurrency, persistence, and messaging. Unlike a web server (e.g., Apache HTTP Server or Nginx), which mainly delivers static content and handles HTTP requests, an application server runs business logic, manages sessions, and interacts with databases to enable dynamic web applications.
If you’re new to this space, this article will get you up to speed quickly. We’ll explore today's leading Java application servers, understand their strengths and limitations, and learn how to select the best fit for your project.
The Most-Used Java Application Servers Today
Today’s most widely used Java application servers reflect the dominant shift toward cloud-native microservices. According to our 2025 Java Developer Productivity Report, 64% of organizations now use microservices, while just 36% still rely on monolithic architectures. Let’s take a closer look at the top three choices and find out why they’ve become so popular.
Source: 2025 Java Developer Productivity Report
Tomcat
Apache Tomcat is the most widely used Java application server, largely due to its lightweight design, fast startup and deployment, and simple configuration — qualities especially valuable in cloud-native and microservices environments, where agility and resource efficiency are critical.
Recent Tomcat versions have significantly enhanced security, delivering hardened default configurations that include restricted management interfaces, the removal of sensitive headers, and features such as rate limiting and prompt updates to address vulnerabilities. These improvements bring Tomcat in line with modern enterprise security standards.
While Tomcat does not provide full Jakarta EE capabilities, its open-source foundation, large developer community, comprehensive documentation, and seamless integration with cloud platforms make it the default choice for most web and API applications.
Jetty
Jetty is a lean, embeddable Java servlet container built for speed and flexibility. Its defining features are a minimal footprint and the ability to run not only standalone but also embedded within larger applications, making it a natural fit for microservices, web servers, and embedded systems.
Its modular architecture means you can integrate only the components your project needs, which improves efficiency and eases maintenance. It’s also highly efficient at handling high levels of concurrency and supports modern protocols such as HTTP/2 and WebSocket, which are key to building responsive applications with real-time communications.
If you need a fast, embeddable, scalable server for microservices or development environments, Jetty is often the better choice. For enterprise-grade, specification-driven applications, Tomcat remains a reliable default.
WildFly (formerly JBoss)
WildFly is a full-featured, standards-compliant Jakarta EE application server that supports enterprise features such as Enterprise JavaBeans (EJB), Java Persistence API (JPA), clustering, security, and transaction management — capabilities not found in Tomcat and Jetty, which are lightweight servlet containers focused solely on Servlet and JavaServer Pages (JSP).
WildFly is ideal for complex, transaction-heavy applications with high-availability needs, but comes at the cost of added complexity and overhead. It was renamed from JBoss in 2014, after the formal separation of the community-driven open-source project (WildFly) and Red Hat’s commercially supported product (JBoss EAP), which remains in use today.
Luckily, knowing when to use it is simple. Choose WildFly when you require a full Jakarta EE environment. And use Tomcat or Jetty for lightweight, straightforward deployments.
Back to topBenefits of Using a Java Application Server
Java application servers play a crucial role in enabling developers to focus on building features rather than managing infrastructure. Three benefits in particular make this possible.
Centralized Application Management
Centralized application management is a key benefit of using a Java application server as it offers a unified platform for deploying and maintaining Java enterprise applications.
Through a single interface, IT teams can oversee application lifecycles, manage shared resources, and enforce security policies — reducing both operational complexity and risk. This centralization ensures consistency in configuration and simplifies troubleshooting across the entire environment.
Scalability (With Some Exceptions)
Java application servers enable applications to efficiently handle increasing user loads and traffic by leveraging built-in support for multi-threading, clustering, and load balancing.
As demand rises, applications can scale out horizontally by adding additional servers to the cluster, which maintains high availability and reliable performance even during traffic surges.
That said, achieving seamless scalability in practice will require careful management of Java Virtual Machine (JVM) internals, application design, and systems integration. Developers will need to rigorously monitor performance and test loads to achieve reliable outcomes.
Enterprise Specification/API Support
Having a platform that standardizes the infrastructure for developing and maintaining complex applications can be a game-changer.
By implementing industry-standard specifications such as Jakarta EE and MicroProfile, Java application servers deliver a consistent set of APIs for essential functions, including transactions, persistence, security, and messaging.
This approach allows developers to focus on business logic and provides portability across vendors and environments.
Back to topDrawbacks of Using a Java Application Server
The power that Java application servers offer is not without its drawbacks, especially compared to lightweight containers or cloud-native Java frameworks (e.g., Spring Boot, Quarkus, Micronaut). Here are the top four challenges you should consider.
Redeploy Times
Redeploying a Java application can take anywhere from 30 seconds to several minutes, with enterprise environments sometimes experiencing delays of five to seven minutes per update. These interruptions frustrate developers and increase operational risk, as redeployment can temporarily make the application unavailable and cause production issues.
The good news is that tools like JRebel can eliminate most redeploy delays by skipping the rebuild-package-redeploy cycle for Java code changes, instantly applying updates directly to the running application in under a second. This maintains session state, avoids server restarts, and lets developers see changes immediately.
Heavy Resource Utilization
Java application servers can consume significantly more memory and CPU, particularly full-scale, enterprise-level servers such as IBM WebSphere or Oracle WebLogic. This increased resource usage stems from the JVM, class loading processes, garbage collection, multithreading, and the extensive enterprise features these servers support.
For example, a basic Jakarta EE server without any deployed applications can consume more than 400MB of RAM, and full enterprise deployments frequently demand gigabytes of memory per server instance. The result? Higher infrastructure costs, slower scaling capabilities, and increased operational complexity.
High Costs and Vendor Lock-In
For decades, perpetual licenses dominated the enterprise software landscape, but the industry has now largely shifted toward recurring cost models — often requiring businesses to pay ongoing licensing fees per core, which can range from thousands to tens of thousands of dollars per year, in addition to annual support fees of 20% or more. For example, Oracle’s top-tier WebLogic Suite bundle is priced at $45,000 per processor, plus recurring support charges.
This shift is compounded by the reality of vendor lock-in: proprietary features, custom integrations, and the need for specialized technical expertise make migrating to another platform both costly and complex. Over time, such lock-in increases operational risk as organizations become dependent on the vendor’s future product direction, the quality of their support, and their pricing decisions.
Complexity
Configuring and deploying Java application servers can be challenging. Properly setting up critical components such as database connection pools, JMS queues, or security realms demands careful attention to detail in XML or proprietary configuration files. Mistakes in these steps can lead directly to application failures or degraded performance.
Even for minor application updates, the typical deployment process involves packaging the application into a .war or .ear file, manually transferring it to the server, and restarting the server, often resulting in several minutes of downtime. While tools like JRebel can reduce deployment friction, this workflow remains a significant constraint.
Given this complexity, enterprises often require specialized personnel with expertise across multiple domains to manage large-scale, mission-critical deployments reliably.
Back to topWhen to Use a Java Application Server
Java application servers are most appropriate when mission-critical enterprise applications require the highest levels of reliability, security, and compliance. Typical use cases for Java application servers include large-scale banking systems, major e-commerce platforms, and government services — scenarios where processing millions of transactions securely and reliably is a core requirement.
Back to topWhen Not to Use a Java Application Server
A full-blown application server is often overkill for modern, lightweight, or cloud-native applications, especially those designed as microservices or simple web APIs.
If your application does not require advanced enterprise features, such as distributed transactions, complex security, or legacy integration, a lightweight servlet container (e.g., Tomcat, Jetty) or a modern framework like Spring Boot can deliver faster startup, lower resource overhead, and easier deployment in cloud and containerized environments.
These alternatives are more developer-friendly, align with DevOps practices, and are better suited for stateless, horizontally scalable services.
Back to topFinal Thoughts
No Java application server is ideal for every scenario. Your decision should reflect the specific needs of your application, your team’s skills, operational priorities, and strategic goals.
To make the best choice, start with proof-of-concept deployments to evaluate real-world performance. Then, select the solution that delivers the most business value for your environment.
Back to topSuffering From Slow Java App Redeploy Times?
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