develop java based process

package org.rahmadnet.learning.ad_callout;

import org.openbravo.dal.service.OBDal;
import org.openbravo.erpCommon.utility.OBError;
import org.openbravo.model.common.businesspartner.BusinessPartner;
import org.openbravo.model.common.enterprise.Organization;
import org.openbravo.scheduling.ProcessBundle;
import org.openbravo.service.db.DalBaseProcess;

public class ExampleJavaProcess extends DalBaseProcess
{

      public void doExecute(ProcessBundle bundle) throws Exception {
        try {

          // retrieve the parameters from the bundle
          final String bPartnerId = (String) bundle.getParams().get("cBpartnerId");
          final String organizationId = (String) bundle.getParams().get("adOrgId");
          final String tabId = (String) bundle.getParams().get("tabId");

          final String myString = (String) bundle.getParams().get("mystring");

          // implement your process here

          // Show a result
          final StringBuilder sb = new StringBuilder();
          sb.append("Read information:<br/>");
          if (bPartnerId != null) {
            final BusinessPartner bPartner = OBDal.getInstance().get(BusinessPartner.class, bPartnerId);
            sb.append("Business Partner: " + bPartner.getIdentifier() + "<br/>");
          }
          if (organizationId != null) {
            final Organization organization = OBDal.getInstance().get(Organization.class,
                organizationId);
            sb.append("Organization: " + organization.getIdentifier() + "<br/>");
          }
          sb.append("MyString: " + myString + "<br/>");

          // OBError is also used for successful results
          final OBError msg = new OBError();
          msg.setType("Success");
          msg.setTitle("Read parameters!");
          msg.setMessage(sb.toString());

          bundle.setResult(msg);

        } catch (final Exception e) {
          e.printStackTrace(System.err);
          final OBError msg = new OBError();
          msg.setType("Error");
          msg.setMessage(e.getMessage());
          msg.setTitle("Error occurred");
          bundle.setResult(msg);
        }
      }
    }