#vulnerable code 
                                public String getDefaultModelWorkdir() {
        String p = configuration.getSettingValueFor(SettingsConstants.DEFAULT_MODEL_WORKDIR).toString();
        if (p == null) {
            throw new RuntimeException("No default model wordking directory set in configuration");
        }

        return p;
    } 
                            #location 2 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public String getDefaultModelWorkdir() {
        Object p = configuration.getSettingValueFor(SettingsConstants.DEFAULT_MODEL_WORKDIR);
        if (p == null) {
            return getRawConfig().get(IMPORT_DIR_CONF_KEY);
        }

        return p.toString();
    }