* (prefixed with {@code env.}).
     *
     * @return the system properties, never {@code null}
     */
    @Nonnull
    Map<String, String> getSystemProperties();

    /**
     * Each invocation computes a new map of effective properties. To be used in interpolation.
     * <p>

                    systemPath = systemPath.replace('/', File.separatorChar).replace('\\', File.separatorChar);
                    String jdkHome =
                            request.getSystemProperties().getProperty("java.home", EMPTY) + File.separator + "..";
                    if (systemPath.startsWith(jdkHome)) {
                        msg += ". Please verify that you run Maven using a JDK and not just a JRE.";