Howto call method from OSGI bundle?

[rcbandit]

I have written this OSGI bundle:

/*
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 * and open the template in the editor.
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package CryptoLib;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class cryptoSha {

    public cryptoSha() {
    }

    /** method for converting simple string into SHA-256 hash */
       public String stringHash(String hash) throws NoSuchAlgorithmException{

            MessageDigest md = MessageDigest.getInstance("SHA-256");
            md.update(hash.getBytes());

            byte byteData[] = md.digest();

            /** convert the byte to hex format */
            StringBuilder sb = new StringBuilder();
                for (int i = 0; i < byteData.length; i++) {
            sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
            }              
           return sb.toString();
       }


}

And this is the Acticator class:

package com.CL77;

    import org.osgi.framework.BundleActivator;
    import org.osgi.framework.BundleContext;

    public class Activator implements BundleActivator {
        private static BundleContext context;

        public void start(BundleContext context) throws Exception {
             Activator.context = context;
        }

        public void stop(BundleContext context) throws Exception {
             Activator.context = null;
        }

    }

This is the EAR package which calls the bundle:

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.osgi.framework.BundleContext;

@Named("loginController")
@SessionScoped
public class userCheck extends HttpServlet implements Serializable {

       public userCheck(){
       }

       private BundleContext bundleContext;

       @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        bundleContext = (BundleContext) config.getServletContext().getAttribute("osgi-bundlecontext");
    }

    @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            cryptoSha dc = new cryptoSha();
            String nhash = dc.stringHash("test");
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }

       }
 }       

I successfully compile and deploy then on JBoss 7.1.0 but when I start the EAR package nothing happens. Can you help me to find where I'm wrong in the code?

kind regards, Peter