Apache Tomcat Server

🛰️ Apache Tomcat Server and Other Java Servers Explained in Detail

🔹 What is Apache Tomcat?

Apache Tomcat is a free, open-source web server developed by the Apache Software Foundation. It is not a full Java EE (Jakarta EE) server, but it implements the Java Servlet, JSP, and WebSocket specifications.

✅ Key Features of Apache Tomcat

Feature	Description
Developed by	Apache Software Foundation
Type	Web server & servlet container (not a full application server)
Supports	Java Servlets, JSP (JavaServer Pages), WebSockets
Platform	Cross-platform (Linux, Windows, macOS)
Protocols	HTTP, HTTPS, AJP
Lightweight	Ideal for small-to-medium scale web applications
Easy Deployment	WAR file deployment
Embeddable	Can be embedded in Java apps (via Spring Boot)
Default Port	8080

⚙️ How Tomcat Works

Client sends HTTP request to Tomcat server.
Tomcat maps the request to a servlet or JSP.
Servlet processes the request and generates a response.
Tomcat returns the HTTP response back to the client.

📁 Directory Structure (Brief)

Folder	Purpose
`bin/`	Startup and shutdown scripts
`conf/`	Configuration files (`server.xml`)
`webapps/`	Location to deploy web apps (WAR folders)
`logs/`	Log files
`lib/`	Libraries required by Tomcat
`work/`	Temporary files compiled by JSP engine

🚀 Common Alternative Java Servers

Server	Type	Description
Tomcat	Web Server + Servlet Engine	Supports servlets, JSP; lightweight and popular
Jetty	Web Server + Servlet Engine	Lightweight, embeddable, used in tools like Eclipse and Maven
GlassFish	Full Java EE Application Server	Official reference implementation of Java EE (Jakarta EE)
WildFly (ex-JBoss)	Full Java EE App Server	High performance, enterprise features, supports clustering
WebLogic	Full Java EE App Server	Developed by Oracle; powerful but commercial
WebSphere	Full Java EE App Server	Developed by IBM; enterprise-grade, robust but complex
Undertow	Lightweight Web Server	Used in WildFly; extremely fast and embeddable
Payara	Fork of GlassFish	More stable and commercial support available

🔄 Comparison: Tomcat vs Full Application Servers

Feature	Tomcat	Full Java EE Servers (e.g., WildFly, GlassFish)
Servlet & JSP Support	✅ Yes	✅ Yes
EJB, JPA, JMS Support	❌ No (needs external lib)	✅ Yes
Lightweight	✅ Yes	❌ Heavier
Startup Time	Fast	Slower
Microservices Ready	✅ With Spring Boot	✅ With configurations
Enterprise Ready	❌	✅ Yes

💡 When to Use What?

Use Case	Recommended Server
Simple web app (Servlet/JSP)	Apache Tomcat
REST APIs with Spring Boot	Tomcat (embedded)
Full Java EE stack (EJB, JMS, JPA, etc.)	WildFly / GlassFish
Large enterprise applications	WebLogic / WebSphere
Embedded Java server inside application	Jetty / Undertow

📦 Tomcat and Spring Boot

Spring Boot includes an embedded Tomcat server by default.
You don’t need to install Tomcat separately — just run the main() method.

@SpringBootApplication
public class MyApp {
   public static void main(String[] args) {
      SpringApplication.run(MyApp.class, args);  // Starts embedded Tomcat
   }
}