What is Apache Tomcat, and how does it work?

Apache Tomcat is one of the most widely used Java application servers. It supports a range of enterprise systems and web applications, making it an important technology for developers and IT teams.

For anyone working with Java, Tomcat provides the environment needed to run web applications. Used across development, testing and live environments, it remains a common choice for deploying Java-based systems.

What is Apache Tomcat?

Apache Tomcat, or simply Tomcat, is an open-source Java application server and servlet container developed by the Apache Software Foundation.

It runs web applications created using a specification called Jakarta Enterprise Edition (for modern versions) or Java Enterprise Edition (for older versions). Both of these are abbreviated to JEE and have several sub-specifications. Tomcat only supports the web specification, which is the most widely used.

In essence, Tomcat is software that allows Java-based websites and applications to run on a server. When a user interacts with a site, by clicking a button or field, Tomcat processes the request and returns the appropriate response.

Tomcat is considered lightweight because it focuses on web functionality rather than the full enterprise platform, making it easier to deploy and manage in many environments. Another advantage is that it can run on different operating systems, including Windows, Linux and macOS. As a free, open-source tool, its popularity is unsurprising.

What is Apache Tomcat used for?

Tomcat is used wherever Java web applications need to be deployed and managed, such as hosting web applications built with servlets and JSP.

It is also widely used in enterprise environments; internal platforms, customer systems and business applications often rely on Tomcat to handle application logic and manage requests in a consistent way.

In addition to these applications, development teams frequently use Tomcat as a local environment. It allows applications to be tested quickly before they are released, which supports faster iteration.

Tomcat is also used to run APIs and backend services. Many systems rely on it to process requests from web or mobile applications and return data as structured text.

Is Apache Tomcat a web or application server?

Tomcat is an application server, although it does include some web server capability.

A web server is designed to deliver static content such as HTML files, images and scripts. It responds to requests by sending files directly to the browser. An application server goes further by running code and generating dynamic content. It processes requests, applies business logic and may interact with databases or other services.

Tomcat falls within this second category. Its main purpose is to run Java applications and produce responses based on user interaction. In many environments, Tomcat is used alongside a dedicated web server. The web server handles static content, while Tomcat manages application logic, which helps to improve efficiency and keep responsibilities clearly defined.

What is the difference between Apache and Apache Tomcat?

Apache HTTP Server is a web server that delivers static content such as web pages and images. It is designed to handle large volumes of requests efficiently.

Apache Tomcat is an application server that runs Java-based applications, processing dynamic content and managing how applications respond to requests.

Although they serve different purposes, they are typically used together. A common approach is to use Apache HTTP Server at the front, with Tomcat handling application processing behind the scenes. Both are developed by the Apache Software Foundation – along with around 300 other tools – which is why they share the same Apache brand name.

How Apache Tomcat works?

So, how does Apache Tomcat work? It processes requests from users and returning responses through a structured flow:

1. When a user visits a website, their browser sends an HTTP request to the server. Tomcat listens for these requests on a defined port.
2. Once the request is received, Tomcat determines which application should handle it. It then routes the request to the appropriate servlet.
3. The servlet processes the request. This may involve retrieving data, applying logic or interacting with other systems. The result is used to generate a response, often as a web page or structured data.
4. Tomcat then sends this response back to the browser, where it is displayed to the user.

Behind this process, Tomcat manages application lifecycles and ensures that requests are handled efficiently, allowing it to support both simple applications and more complex systems.

Why Apache Tomcat remains widely used

Tomcat continues to be widely adopted because it is both reliable and has a long history of use in production environments, which makes it a trusted option for many organisations. Teams are familiar with how it works and how to manage it.

It also adapts well. Tomcat can be used on its own or as part of a larger architecture, depending on requirements.

Its lightweight design makes it easier to configure compared to more complex platforms. This is particularly useful for teams that want a focused solution for web applications.

As an open-source tool, it is accessible without licensing costs, allowing organisations to use and adapt it as they need.

Learn Apache Tomcat with StayAhead

Learning Apache Tomcat is a valuable skill for anyone working with Java web technologies. It supports application deployment and helps teams manage how systems respond to user requests.

For developers, understanding Tomcat improves the ability to build and deploy applications. For system administrators, it provides insight into how web platforms operate in practice.

StayAhead offers Apache Tomcat training designed to build practical skills in configuration and application management. Contact us now to add Apache Tomcat to your evolving skillset.