What is Tomcat? Everything You Need to Know

What is Tomcat? 

Tomcat is an open-source web server and servlet. The Apache Software Foundation has developed it. It is used widely for hosting Java-based applications on the web. It is built on Java technologies and implements the Java Servlet and JavaServer Pages (JSP) specifications. Tomcat acts as a bridge between web servers and Java-based applications, facilitating the execution of dynamic content and processing client requests.

Tomcat offers a lightweight and efficient solution for hosting Java web applications. Tomcat is popular for several reasons. Its scalability is admired by many. Tomcat's robustness is useful. It has great community support which brings relief to the users. With its modular architecture and adherence to industry standards, Tomcat enables developers to build and deploy web applications with ease.

How Does Tomcat Work? 

Tomcat follows a modular architecture comprising connectors, containers, and the Catalina Servlet container. This architecture enables Tomcat to efficiently handle client requests and generate responses.

Connectors are in charge of accepting and processing requests that the clients sent to Tomcat. In order to have a connection with the client, different protocols are used by the connectors. These connectors can be HTTP or HTTPS. They handle tasks like connection management, request parsing, and data transmission.

Once a request is received, connectors pass it to the appropriate container based on the requested URL. Containers manage the lifecycle of web applications and execute Java servlets or JSP code to generate responses. They provide an environment for running web applications, managing resources, and handling concurrent requests.

The Catalina Servlet container, in particular, is responsible for mapping requests to the appropriate servlet and managing the servlet's life cycle. It handles the process of generating dynamic content by executing servlet code and producing the response that is sent back to the client.

Tomcat's modular architecture allows for flexibility and extensibility. Developers can add or customize components to enhance the functionality of Tomcat according to their specific requirements.

How to Install Tomcat on Windows?

Step 1. Command-line installation

Installing Tomcat on Windows is easy. It is a step-by-step process. Go to the Apache Tomcat website. Once you go there, check for the recent Tomcat version and download it. You should check what your system needs before you download it. Also, check the capacity of your system. 

When the download is done, the downloaded archive should be extracted. Save the downloaded file in a directory on your computer. 

This directory will serve as the Tomcat installation directory.

To configure Tomcat, you need to set up essential environment variables. 

The JAVA_HOME variable should indicate where the  Java Development Kit (JDK) is located on your system. The CATALINA_HOME variable should point to the Tomcat installation directory. These variables are crucial for Tomcat to locate the necessary files and execute them properly.

Step 2. Start Tomcat

After setting up the environment variables, you can start Tomcat. You can start Tomcat in different ways. It can be run as a service or the startup scripts that are given can be used.  You can also start it in manual mode from the command line.

When Tomcat starts, it binds to a specific port, typically 8080 by default. By launching a web browser and going to http://localhost:8080/, you can view the deployed applications and Tomcat server through this port.

How to Deploy an Application in Tomcat?

Deploying a web application in Tomcat involves a straightforward process. Tomcat uses a concept called the Web Application Archive (WAR) file to package and deploy web applications.

You first need to build an application as a WAR file in order to get it deployed. 

The WAR file contains all the necessary components of your web application, including servlets, JSP files, HTML files, and resource files.

Once you have the WAR file, copy it to the "web apps" directory within the Tomcat installation directory. Tomcat automatically deploys the application by unpacking the WAR file and creating the necessary directory structure.

By default, the context path of the deployed application is derived from the WAR file name. For example, name your WAR file myapp.war to access the application at http://localhost:8080/myapp/ 

Tomcat provides various configuration options to customize the deployment process. You can configure additional settings using XML files or annotations, such as specifying context parameters, defining servlet mappings, or configuring data source connections.

Once the application is deployed, you can access it through the assigned context path and interact with its functionality through the web browser.

Tomcat vs. Other Web Servers 

Tomcat vs. Jetty

Tomcat and Jetty are both popular choices for Java web application hosting. While Tomcat is widely adopted, Jetty offers better performance for high-concurrency scenarios due to its efficient architecture. Jetty is known for its small footprint and fast startup time, making it suitable for microservices and embedded systems. On the other hand, Tomcat provides stability, robustness, and extensive community support.

Tomcat vs. Nginx

Tomcat and Nginx serve different purposes in web application deployment. Tomcat is a servlet container, while Nginx is a web server. They can be used together to create a high-performance setup, with Nginx acting as a reverse proxy in front of Tomcat. Nginx can handle static content, load balancing, and caching, while Tomcat focuses on executing Java servlets and JSP.

Tomcat vs. WildFly

Tomcat and WildFly (formerly known as JBoss) are both Java application servers. Tomcat is lightweight and straightforward, focusing on servlet and JSP execution. On the other hand, WildFly offers more extensive features, including support for Java Enterprise Edition (EE) specifications, advanced management capabilities, and clustering for high availability.

Tomcat vs. Httpd

Tomcat and Apache HTTP Server (Httpd) have different purposes. Tomcat specializes in Java web application execution, while Httpd is a general-purpose web server supporting multiple scripting languages. They can be used together, with Httpd serving as a front-end proxy to Tomcat or handling static content, while Tomcat executes the dynamic parts of the application.

Tomcat vs. WebLogic Server

Both the servers, Oracle WebLogic Server and Tomcat are application servers. However, they have differences between them. You can find differences in how their features are, how scalable they are and what their capabilities are at the enterprise level. Tomcat is lightweight and suitable for smaller applications, while WebLogic Server is designed for enterprise-level applications with high scalability and complex requirements. WebLogic Server provides advanced features like distributed caching, high availability, and support for Java EE specifications.

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Conclusion 

Tomcat, as an open-source web server and servlet container, provides a reliable platform for hosting Java-based web applications. Developers choose it for a lot of reasons. The reasons are that it is lightweight and simple to set up. Moreover,  it works with different operating systems. With Tomcat, developers can efficiently build and deploy robust web applications, taking advantage of its seamless execution of Java servlets and JSP.

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If you have any questions or queries, feel free to post them in the comments section below. Our team will get back to you at the earliest.

FAQs 

1. Is Tomcat an app server or a web server?

This answers the question, what is Tomcat. Tomcat functions primarily as a web server and servlet container. It can, however, also operate as an application server. You must include elements like Java Transaction API (JTA) and Java Message Service (JMS) in order to accomplish it. 

2. What is the difference between Apache and Tomcat?

Apache HTTP Server (Httpd) is a general-purpose web server that supports various scripting languages and modules. Tomcat, on the other hand, is specifically designed for running Java web applications as a servlet container, providing native support for the Java Servlet and JSP specifications.

3. What is the advantage of Apache Tomcat?

Apache Tomcat offers easy installation, lightweight performance, and excellent support for Java servlets and JSP. The environment that Tomcat provides is not only reliable, it is robust and it can be scaled. 

4. What is Tomcat in the context of web servers?

Tomcat, also known as Apache Tomcat, is an open-source web server and servlet container developed by the Apache Software Foundation.

5. What are the primary functions of Tomcat?

Tomcat is designed to serve Java web applications and it provides a "pure Java" HTTP web server environment for running Java code.

6. Is Apache Tomcat free to use?

Yes, Apache Tomcat is an open-source software, which means it can be used without cost under the Apache License 2.0.

7. What types of applications can run on Apache Tomcat?

Tomcat is primarily used for executing Java Servlet, Java Expression Language, and Java WebSocket technologies.

8. How does Tomcat compare with other web servers?

While Tomcat is dedicated to serving Java applications, other web servers like Apache or Nginx are more general-purpose and support a broader range of programming languages.

9. Why is Tomcat used in Spring Boot?

If you are thinking about what tomcat is used for, here is the answer. Tomcat is commonly used as the embedded web server in Spring Boot applications due to its seamless integration with the Spring framework. Spring Boot simplifies the development process, and Tomcat's ability to deploy and run Java web applications makes it an ideal choice for Spring Boot projects.

10. Is 8080 the default port of Tomcat?

Yes, 8080 is the default port used by Tomcat to listen for HTTP requests. However, this port can be changed in the server configuration files if required.