Connecting a tomcat project app with mysql on open

Im trying to make a simple tomcat-mysql connection on openshift. But when i run it on the server it shows a HTTP Status 404 error and i dont know why . Here there are my main files :

Java Class:

    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException; 

    public class DB_Info {
    public static final String MYSQL_USERNAME = System.getenv("OPENSHIFT_MYSQL_DB_USERNAME");
    public static final String MYSQL_PASSWORD = System.getenv("OPENSHIFT_MYSQL_DB_PASSWORD");
    public static final String MYSQL_DATABASE_HOST = System.getenv("OPENSHIFT_MYSQL_DB_HOST");
    public static final String MYSQL_DATABASE_PORT = System.getenv("OPENSHIFT_MYSQL_DB_PORT");
    public static final String MYSQL_DATABASE_NAME = "brooker";
    private static Connection con;
    /**
     * returns connection to DB
     * @param con Connection
     */
    public static String initConnection(){
        String url = "";
        if(con==null){
            try {
                url = "jdbc:mysql://" + MYSQL_DATABASE_HOST + ":" + MYSQL_DATABASE_PORT + "/" + MYSQL_DATABASE_NAME;
                con = DriverManager.getConnection(url, MYSQL_USERNAME, MYSQL_PASSWORD);
            } catch (SQLException e) {
                e.printStackTrace();
                return e.getMessage();
            }
        }
        return "Connection Initialized!";
    }

    public static Connection getConnection() {
        if (con == null) {
            initConnection();
        }
        return con;
    }
}

My web.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">

    <display-name>HelloWorld Application</display-name>
    <description>
    This is a simple web application with a source code organization
    based on the recommendations of the Application Developer's Guide.
    </description>

<servlet>
    <servlet-name>DB_Info</servlet-name>
    <servlet-class>DB_Info</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>DB_Info</servlet-name>
    <url-pattern>/DB_Info</url-pattern>
</servlet-mapping>
</web-app>

And my pom.xml file :

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>brooker</groupId>
<artifactId>brooker</artifactId>
<packaging>war</packaging>
<version>1.0</version>
<name>brooker</name>
<repositories>
    <repository>
        <id>eap</id>
        <url>http://maven.repository.redhat.com/techpreview/all</url>
        <releases>
            <enabled>true</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>
<pluginRepositories>
    <pluginRepository>
        <id>eap</id>
        <url>http://maven.repository.redhat.com/techpreview/all</url>
        <releases>
            <enabled>true</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </pluginRepository>
</pluginRepositories>
<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.6</maven.compiler.source>
    <maven.compiler.target>1.6</maven.compiler.target>
</properties>
<dependencies>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>9.2-1003-jdbc4</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.25</version>
    </dependency>           
</dependencies>
<profiles>
    <profile>
        <!-- When built in OpenShift the 'openshift' profile will be used when 
            invoking mvn. -->
        <!-- Use this profile for any OpenShift specific customization your app 
            will need. -->
        <!-- By default that is to put the resulting archive into the 'webapps' 
            folder. -->
        <!-- http://maven.apache.org/guides/mini/guide-building-for-different-environments.html -->
        <id>openshift</id>
        <build>
            <finalName>brooker</finalName>
            <plugins>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>2.1.1</version>
                    <configuration>
                            <outputDirectory>webapps</outputDirectory>
                        <warName>ROOT</warName>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </profile>
</profiles>
</project>

Does anyone have a idea ?

Update: I made it work just by copying ROOT.war from ~/app-root/runtime/repo/deployments/ to ~/jbossews//webapps/

but now it shows this error message :

HTTP Status 500 - Error instantiating servlet class DB_Info

type Exception report

message Error instantiating servlet class DB_Info

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error instantiating servlet class DB_Info
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1008)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    java.lang.Thread.run(Thread.java:744)
root cause

java.lang.ClassNotFoundException: DB_Info
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1008)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    java.lang.Thread.run(Thread.java:744)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.40 logs.

UPDATE: I changed the servlet into :

import java.io.*;

//import java.util.*;
//import javax.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

//krijojme nje klase qe zgjaton superclassen HttpServlet
public class DBConnection extends HttpServlet {
      public static final String MYSQL_USERNAME = System.getenv("OPENSHIFT_MYSQL_DB_USERNAME");
      public static final String MYSQL_PASSWORD = System.getenv("OPENSHIFT_MYSQL_DB_PASSWORD");
      public static final String MYSQL_DATABASE_HOST = System.getenv("OPENSHIFT_MYSQL_DB_HOST");
      public static final String MYSQL_DATABASE_PORT = System.getenv("OPENSHIFT_MYSQL_DB_PORT");
      public static final String MYSQL_DATABASE_NAME = "brooker";
  /**
     * kjo ketu nuk e di per cfare perdoret po duhet vene 
     */
    private static final long serialVersionUID = 1L;

    //krijojme nje metode te klases HttpServlet me emrin service 
    //dhe qe merr 2 parametra nje reqyest dhe nje response 
    //si dhe hedh disa lloje gabimesh si psh input out exeption 
    //si dhe servlet Exception
public void service(HttpServletRequest request,
  HttpServletResponse response)
  throws IOException, ServletException{
    //ketu tregon si do te jete pergjigja jone ne kete rast e duam html
  response.setContentType("text/html");
  //dhe fillojme te paraqisim
  PrintWriter out = response.getWriter();
  out.println("<html>");
  out.println("<head><title>Servlet JDBC</title></head>");
  out.println("<body>");
  out.println("<h1>Servlet JDBC</h1>");
  out.println("</body></html>");  
  // connecting to database
  //krijon ketu parametrat per tu lidhur me databasin

  Connection con = null;   //lidhjen
  Statement stmt = null; //queryn qe do te bejme
  ResultSet rs = null; //te dhenat qe do marrim
  try {

  Class.forName("com.mysql.jdbc.Driver"); 

  //String url = "jdbc:mysql://" + MYSQL_DATABASE_HOST + ":" + MYSQL_DATABASE_PORT + "/" + MYSQL_DATABASE_NAME;
  //con = DriverManager.getConnection(url, MYSQL_USERNAME, MYSQL_PASSWORD);
  String url = "jdbc:mysql://" + MYSQL_DATABASE_HOST + ":" + MYSQL_DATABASE_PORT + "/" + MYSQL_DATABASE_NAME;
  con = DriverManager.getConnection(url, MYSQL_USERNAME, MYSQL_PASSWORD);


  }
  //dhe ketu hudh kap gabimet e mundshme qe hudh klasa me larte
  } catch (SQLException e) {
 throw new ServletException("Servlet Could not display records.", e);
  } catch (ClassNotFoundException e) {
  throw new ServletException("JDBC Driver not found.", e);
  } finally {
  try {
  if(rs != null) {
  rs.close();
  rs = null;
  }
  if(stmt != null) {
  stmt.close();
  stmt = null;
  }
  if(con != null) {
  con.close();
  con = null;
  }
  } catch (SQLException e) {}
  }
  out.close();
  }
  }

but i still get the javax.servlet.ServletException: Error instantiating servlet class DBConnection

and java.lang.ClassNotFoundException: DBConnection