Tomcat datasource connection pooling
http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html#Non%20DBCP%20Solutions

private static void initializeDataSource(String whichOne) throws NamingException, SQLException{
 logger.debug("entering initializeDataSource("+whichOne+")");
        
       try{
          InitialContext ic = new InitialContext();
          
          if(whichOne.equals(AppHelper.SC_DEFAULT_DS_CON)){        
         //if (dataSource == null)
          dataSource = (DataSource) ic.lookup(whichOne);  
          }
       }catch (NamingException ne){
           throw new NamingException("NamingException while looking" +
                   " up DataSource Connection " + whichOne
                   + ": \n" + ne.getMessage());
       }
 logger.debug("leaving initializeDataSource()");        
   }