}

    @Override
    public ProjectBuildingRequest setSystemProperties(Properties systemProperties) {
        if (systemProperties != null) {
            this.systemProperties = SystemProperties.copyProperties(systemProperties);
        } else {
            this.systemProperties.clear();
        }

        return this;
    }

    @Override
    public Properties getUserProperties() {

        return this;
    }

    @Override
    public MavenExecutionRequest setSystemProperties(Properties properties) {
        if (properties != null) {
            this.systemProperties = SystemProperties.copyProperties(properties);
        } else {
            this.systemProperties = null;
        }

        return this;
    }

    @Override