jndi failure

try {
            InitialContext  ic  = new InitialContext();
            
            NamingEnumeration<NameClassPair> thingies = ic.list( "java:comp/env/jndi" );
            
            while( thingies.hasMore() ) {
                NameClassPair ncPair = thingies.next();
                System.out.println( ncPair.getName() );
                retString += ncPair.getName() + " : " + ncPair.getClassName() + " --";
            }
} catch (NamingException nex) {
            //System.out.println( nex.getExplanation() );
            //nex.printStackTrace();
            retString = "Error :" + nex.getExplanation();
}