Tomcat 7-Google Oauth2-ClassNotFoundException-Java-Eclipse

Question

I am trying to get offline access to my google calendar. This question has been answered before here: Offline Access to google calendar using java but for some reason I always get an ClassNotFoundException, when trying to authenticate.

I am running the application locally on an Apache Tomcat 7 Server and use Eclipse Mars. I installed the following APIs via the Google API ManagerPlugin:

• Google OAuth2 API v2
• (Google OAuth API v1) The plugin tells me, that v2 is preferred
• Google Calendar API

Usually I copy external jar-files to the WEB-INF/lib folder and to the Tomcat/lib folder but I guess the plugin does this for me right? All API's are listed on my JavaBuildPath.

If I run the same functions as Java Application it works, so something must be wrong with the Tomcat settings.

Did anyone have such an issue before and can help me? Thanks in advance.

Servlet (Credentials removed):

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    response.getWriter().append("Served at: ").append(request.getContextPath());
    this.authenticate(request, response);
}


 public void authenticate(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

        String client_id                = "";
        String redirect_uri             = "";
        String scope                    = "https://www.googleapis.com/auth/calendar";
        String client_secret            = "";
        List <String> scopes;
        HttpTransport transport         = new NetHttpTransport();
        JsonFactory jsonFactory         = new JacksonFactory();

        scopes = new LinkedList<String>();
        scopes.add(scope);
        GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(transport, jsonFactory, client_id, client_secret, scopes).build();
        GoogleAuthorizationCodeRequestUrl url = flow.newAuthorizationUrl();
        url.setRedirectUri(redirect_uri);
        url.setApprovalPrompt("force");
        url.setAccessType("offline");
        String authorize_url = url.build();
        response.sendRedirect(authorize_url);
    }

Console:

java.lang.ClassNotFoundException: com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow$Builder
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1854)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1703)
at net.meetme.CalendarServlet.authenticate(CalendarServlet.java:88)
at net.meetme.CalendarServlet.doGet(CalendarServlet.java:42)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

Answer 1

Thank you for your fast replies. I deployed all the jar-files to my WEB-INF/lib.

The mistake was that I also added all the jar-files to the Java Build Path. You just need to remove these jar- files from the build path and it works.