creating connection using sessionId and target url in salesForce.com using java

public PartnerConnection connect(String sessionId,
            String targetUrl)
            throws ConnectionException {
        PartnerConnection connection;
        ConnectorConfig config = new ConnectorConfig();
        config.setServiceEndpoint(targetUrl);
        config.setSessionId(sessionId);
        try {
            connection = Connector.newConnection(config);
        } catch (ConnectionException e) {
            throw e;
        }

        return connection;
    }