private String getEnvironmentSafeKey(String key) {
        String environmentSafeKey = StringUtils.replace(key, ".", "_");
        environmentSafeKey = StringUtils.replace(environmentSafeKey, "-", "_");

        return environmentSafeKey.toUpperCase(Locale.ENGLISH);
    }
Gets value from environment via {@link System#getenv}
@param key key to retrieve
@param defaultValue value to default to if none found
@return value found or default if none
core/src/main/java/com/github/dozermapper/core/config/resolvers/SystemEnvironmentSettingsResolver.java