Connection conn = null;
Context context = null;

try {
   Class.forName(driver);

   // create parameter list to access naming system
   Hashtable parms = new Hashtable();
   parms.put(Context.INITIAL_CONTEXT_FACTORY, CNInitialContextFactory.class.getName());

   // access naming system
   context = new InitialContext(parms);

   // get DataSource factory object from naming system
   dataSource = (DataSource) context.lookup(dataSourceName);
   conn = dataSource.getConnection(userID, password);
} catch (Throwable t) {
   System.err.println("Get connection failed.");
   t.printStackTrace();
} finally {
   try {
       if (context != null) {
           context.close();
       }
   } catch(Exception e) {
       System.err.println("Context close error.");
       e.printStackTrace();
   }
}