tomcat

Pros of Spring Boot

• Simplified configuration with auto-configuration and starter dependencies
• Faster development and deployment with embedded servers and executable JARs
• Rich ecosystem of Spring projects and integrations

Cons of Spring Boot

• Steeper learning curve for developers new to the Spring ecosystem
• Potential for "magic" behavior due to auto-configuration
• Larger application size due to embedded dependencies

Code Comparison

Tomcat (web.xml configuration):

<servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>com.example.MyServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/myservlet</url-pattern>
</servlet-mapping>

Spring Boot (Java configuration):

@RestController
public class MyController {
    @GetMapping("/myendpoint")
    public String handleRequest() {
        return "Hello, Spring Boot!";
    }
}

Spring Boot simplifies configuration and reduces boilerplate code compared to traditional Tomcat setups. While Tomcat provides a robust and flexible servlet container, Spring Boot offers a more opinionated and streamlined approach to application development, especially for microservices and cloud-native applications.

Pros of Netty

• Higher performance and scalability for non-blocking I/O operations
• More flexible and customizable for building network applications
• Better suited for modern, event-driven architectures

Cons of Netty

• Steeper learning curve due to its lower-level API
• Less out-of-the-box functionality compared to Tomcat's full servlet container
• Requires more manual configuration for web applications

Code Comparison

Tomcat (Servlet-based):

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().println("Hello, World!");
    }
}

Netty (Channel-based):

public class HelloServerHandler extends SimpleChannelInboundHandler<HttpRequest> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpRequest req) {
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, Unpooled.wrappedBuffer("Hello, World!".getBytes()));
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }
}

The code comparison illustrates the difference in approach between Tomcat's servlet-based model and Netty's channel-based model. Tomcat provides a higher-level abstraction with its servlet container, while Netty offers more fine-grained control over network operations at the cost of increased complexity.

Pros of Undertow

• Lightweight and high-performance web server with lower memory footprint
• Designed for both blocking and non-blocking architectures
• Supports HTTP/2 and WebSocket protocols out of the box

Cons of Undertow

• Smaller community and ecosystem compared to Tomcat
• Less extensive documentation and fewer learning resources available
• Limited support for JSP (JavaServer Pages) without additional configuration

Code Comparison

Undertow server setup:

Undertow server = Undertow.builder()
    .addHttpListener(8080, "localhost")
    .setHandler(new HttpHandler() {
        @Override
        public void handleRequest(HttpServerExchange exchange) throws Exception {
            exchange.getResponseSender().send("Hello World");
        }
    }).build();
server.start();

Tomcat server setup:

Tomcat tomcat = new Tomcat();
tomcat.setPort(8080);
tomcat.getConnector();
Context ctx = tomcat.addContext("", null);
Tomcat.addServlet(ctx, "hello", new HttpServlet() {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        resp.getWriter().write("Hello World");
    }
});
ctx.addServletMappingDecoded("/*", "hello");
tomcat.start();

Both examples demonstrate a simple "Hello World" server setup, highlighting the differences in API and configuration between Undertow and Tomcat.

Pros of Jetty

• Lighter weight and more modular architecture
• Better suited for embedding in applications
• Faster startup time and lower memory footprint

Cons of Jetty

• Smaller community and ecosystem compared to Tomcat
• Less extensive documentation and learning resources
• Fewer out-of-the-box features for enterprise environments

Code Comparison

Jetty configuration (jetty.xml):

<Configure id="Server" class="org.eclipse.jetty.server.Server">
  <Set name="handler">
    <New id="Handlers" class="org.eclipse.jetty.server.handler.HandlerCollection">
      <Set name="handlers">
        <Array type="org.eclipse.jetty.server.Handler">
          <Item>
            <New id="Contexts" class="org.eclipse.jetty.server.handler.ContextHandlerCollection"/>
          </Item>
        </Array>
      </Set>
    </New>
  </Set>
</Configure>

Tomcat configuration (server.xml):

<Server port="8005" shutdown="SHUTDOWN">
  <Service name="Catalina">
    <Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />
    <Engine name="Catalina" defaultHost="localhost">
      <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true">
      </Host>
    </Engine>
  </Service>
</Server>

Both Jetty and Tomcat are popular Java servlet containers, but they have different strengths. Jetty is more lightweight and modular, making it ideal for embedding in applications, while Tomcat offers a more comprehensive feature set and larger ecosystem, better suited for enterprise environments.

Pros of WildFly

• More comprehensive Java EE implementation, supporting a wider range of enterprise features
• Better clustering and load balancing capabilities out-of-the-box
• Modular architecture allowing for easier customization and reduced memory footprint

Cons of WildFly

• Steeper learning curve due to increased complexity
• Potentially higher resource consumption for smaller applications
• Less widespread adoption compared to Tomcat, potentially leading to a smaller community and fewer resources

Code Comparison

WildFly configuration (standalone.xml):

<subsystem xmlns="urn:jboss:domain:datasources:5.0">
    <datasources>
        <datasource jndi-name="java:jboss/datasources/ExampleDS" pool-name="ExampleDS" enabled="true" use-java-context="true">
            <connection-url>jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE</connection-url>
            <driver>h2</driver>
        </datasource>
    </datasources>
</subsystem>

Tomcat configuration (server.xml):

<GlobalNamingResources>
    <Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"
              maxTotal="100" maxIdle="30" maxWaitMillis="10000"
              username="root" password="password" driverClassName="com.mysql.jdbc.Driver"
              url="jdbc:mysql://localhost:3306/testdb"/>
</GlobalNamingResources>