call google api from servlet

I tried to call getGmail from my servlet command, but keep getting error and I don't know where went, can someone help?

public class GmailCommand implements Command
{
    public GmailCommand() { }

    public String execute(HttpServletRequest request, HttpServletResponse response) 
        throws ServletException, IOException
    {

        try 
        {
            GetGmail.run(null, null);
        } 
        catch (Exception e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "/welcome.jsp";
    }
}

public class GetGmail 
{
    //public static void main(String[] args) throws Exception {
    public static ArrayList<String[]> run(String username, String password)
        throws Exception 
    {
        ArrayList<String[]> result = null;
        System.out.println("GetGmail");
        Properties props = System.getProperties();
        props.setProperty("mail.store.protocol", "imaps");
        props.setProperty("mail.imap.port", "993");
        props.setProperty("mail.imap.connectiontimeout", "5000");
        props.setProperty("mail.imap.timeout", "5000");

        try 
        {
            Session session = Session.getDefaultInstance(props, null);
            Store store = session.getStore("imaps");
            //store.connect("imap.googlemail.com", username, password);
            //sendMessage(session);
            result = readMessage(store);
            store.close();
        } 
        catch (NoSuchProviderException e) 
        {
            e.printStackTrace();
            System.exit(1);
        } 
        catch (MessagingException e) 
        {
            e.printStackTrace();
            System.exit(2);
        }

        //  for(String[] ss:result){
        //      System.out.println(ss[0]+ss[1]+ss[2]+ss[3]);
        //  }

        return result;
    }

this is the error message

SEVERE: Servlet.service() for servlet dispatcher threw exception
java.lang.ClassNotFoundException: javax.mail.NoSuchProviderException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1386)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1232)
at com.web.command.GmailCommand.execute(Gmail开发者_如何学PythonCommand.java:35)
at com.web.commandController.ControllerServlet.processRequest(ControllerServlet.java:46)
at com.web.commandController.ControllerServlet.doPost(ControllerServlet.java:40)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:619)

java.lang.ClassNotFoundException: javax.mail.NoSuchProviderException

You need to have the JavaMail jar file in your classpath (in your case probably in WEB-INF/lib).

This is not included in the standard edition (only in the enterprise edition) of Java, but you can just add the jar file.