Apache Tomcat is an open-source Java Servlet Container developed by the Apache Software Foundation (ASF). It implements several Java Enterprise Edition (Java EE) specifications, including Java Servlet, JavaServer Pages (JSP), and WebSocket, among others. Tomcat is widely used to deploy and run Java web applications.
Category: Application Server / Servlet Container
Primary Purpose: Tomcat is designed specifically to run Java-based web applications. It implements Java Servlet, JSP (JavaServer Pages), and WebSocket specifications, and it allows you to deploy and run Java web apps.
Typical Use: Used to serve dynamic Java web applications and process requests that require server-side logic written in Java. It is not commonly used as a static content web server.
Strengths: Handles Java applications natively. If your application uses Java servlets or JSP, Tomcat is a good fit.
Servlet and JSP Support: Tomcat provides a platform for running Java Servlets and JSP pages, which are essential for building dynamic web applications.
HTTP Web Server: It can handle HTTP requests, making it a lightweight web server.
Open-Source: Tomcat is available under the Apache License, making it freely available for development and deployment.
Scalability: It supports clustering and load balancing, making it suitable for large-scale applications.
Extensibility: Tomcat can be extended with various modules and connectors, allowing integration with other technologies.
Security: Tomcat includes security features such as SSL/TLS support, role-based access control, and integration with JAAS (Java Authentication and Authorization Service).
Management: Tomcat provides a web-based management console and command-line tools for configuration and monitoring.
Catalina: The core component of Tomcat responsible for executing servlets.
Coyote: A connector that allows Tomcat to receive HTTP requests. It can also handle HTTPS.
Jasper: The JSP engine that converts JSP files into servlets for execution by Catalina.
Cluster: Provides session replication and failover features in a clustered environment.
Valves and Filters: Components that allow request filtering, logging, and other pre-processing tasks.
Tomcat Native: An optional component that provides better performance and scalability by using native OS capabilities.
How to Set Up Apache Tomcat on a Linux Server
The main configuration file for Tomcat is server.xml. It contains settings for connectors, engines, hosts, and contexts. Below is an example of a simple connector setup from server.xml:
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
To secure your Tomcat installation, consider the following:
tomcat-users.xml file to define roles and restrict access to management interfaces.server.xml to handle concurrent requests efficiently.logging.properties to capture important events and errors.