Apache Tomcat Tutorial

What is Tomcat? Apache Tomcat is an open-source servlet container (also called a servlet/JSP engine) and web server. It implements the Jakarta Servlet, JSP, EL and WebSocket ...

Requirements Tomcat 10 needs Java 11+, Tomcat 11 needs Java 17+. Check your Java first: Install on Ubuntu Install from a Tarball (portable) Stop and Restart Environment Variables ...

The Layout conf - The Brains server.xml - ports, connectors, engine, hosts, global resources. web.xml - default servlet mappings, welcome files, MIME types. context.xml - defaults ...

What is a WAR? A WAR (Web Application Archive) packages your webapp: classes, JSPs, static resources and a WEB-INF/web.xml . Tomcat loads it into a context . Standard Layout ...

What a Connector Does A connector accepts TCP connections and produces HTTP requests for the engine. This is where ports, timeouts, thread pools and protocols are configured in ...

Set Up a Virtual Host Serve several domains from one Tomcat using <Host> elements in server.xml: Terms Host - maps a domain (with aliases) to a set of apps. Context - one webapp; ...

Why JNDI? A JNDI DataSource is a connection pool managed by Tomcat. Your app looks it up by name instead of creating its own connections - pooling, failover and quotas are ...

Create a Keystore Use a certificate from Let's Encrypt or any CA. Self-signed is fine for testing: Configure the Connector Edit conf/server.xml - uncomment and set: Restart and ...

What You Get Enable Access Logs Add a Valve to your Host in server.xml to record every request: %h = remote host, %t = time, %r = request line, %s = status, %b = bytes. Analyise ...

JVM Memory Set heap sizes in bin/setenv.sh (create it if missing): Do not set Xmx higher than free RAM; the JVM and the OS need headroom. Tune with -Xss1m only if you see ...

Why Systemd Running Tomcat via systemd gives you auto-start on boot, automatic restarts, logs in the journal and clean privilege dropping for ports 80/443. Create the Service ...

Remove Everything You Do Not Need Restrict the Manager Protect manager/host-manager with a strong user and restrict by remote IP: Never enable manager-gui on public-facing ...