import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class HelloWorldServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<h1>Hello World</h1>");
out.println("</body></html>");
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_4_0.xsd" version="4.0">
<display-name>MyApp</display-name>
<servlet>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>com.example.HelloWorldServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldServlet</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>
</web-app>
<subsystem xmlns="urn:jboss:domain:datasources:5.0">
<datasources>
<datasource jndi-name="java:jboss/datasources/MyDataSource" pool-name="MyDataSource" enabled="true" use-java-context="true">
<connection-url>jdbc:mysql://localhost:3306/mydatabase</connection-url>
<driver-class>com.mysql.jdbc.Driver</driver-class>
<driver>mysql</driver>
<pool>
<min-pool-size>5</min-pool-size>
<max-pool-size>20</max-pool-size>
</pool>
<security>
<user-name>myuser</user-name>
<password>mypassword</password>
</security>
<validation>
<validate-on-match>false</validate-on-match>
<background-validation>false</background-validation>
</validation>
</datasource>
<drivers>
<driver name="mysql" module="com.mysql.jdbc">
<driver-class>com.mysql.jdbc.Driver</driver-class>
</driver>
</drivers>
</datasources>
</subsystem>
