RegexBasedInterpolator interpolator = new RegexBasedInterpolator();

        interpolator.addValueSource(new MapBasedValueSource(request.getSession().getUserProperties()));

        interpolator.addValueSource(new MapBasedValueSource(request.getSession().getSystemProperties()));

        try {
            interpolator.addValueSource(new EnvarBasedValueSource());
        } catch (IOException e) {

            DefaultToolchainsBuildingRequest req = new DefaultToolchainsBuildingRequest();
            if (request.getGlobalToolchainsSource().isPresent()) {
                req.setGlobalToolchainsSource(new MappedToolchainsSource(
                        request.getGlobalToolchainsSource().get()));
            } else if (request.getGlobalToolchainsPath().isPresent()) {
                req.setGlobalToolchainsSource(new org.apache.maven.building.FileSource(

            try (InputStream in = Files.newInputStream(userToolchainsFile.toPath())) {
                toolchains = new PersistedToolchains(new MavenToolchainsStaxReader().read(in));
            } catch (Exception e) {
                throw new MisconfiguredToolchainException(
                        "Cannot read toolchains file at " + userToolchainsFile.getAbsolutePath(), e);
            }