List<Toolchain> toolchains = toolchainManager.getToolchains(session, "unknown", null);

        assertEquals(0, toolchains.size());
        verify(logger).error("Missing toolchain factory for type: unknown. Possibly caused by misconfigured project.");
    }

    @Test
    void testModelAndFactory() {
        MavenSession session = mock(MavenSession.class);

        IOException ioEx = new IOException("Unable to establish loopback connection", connEx);
        MojoExecutionException mojoEx =
                new MojoExecutionException("Error executing Jetty: Unable to establish loopback connection", ioEx);

        ExceptionHandler exceptionHandler = new DefaultExceptionHandler();
        ExceptionSummary exceptionSummary = exceptionHandler.handleException(mojoEx);

         * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from
         * aftereffects and bogus error messages.
         */
        List<Dependency> dependencies = model.getDependencies();
        Map<String, Dependency> normalized = new LinkedHashMap<>(dependencies.size() * 2);

     * so.
     *
     * @param rootProject The root project that is being built.
     * @param buildResumptionData Information needed to resume the build.
     * @throws BuildResumptionPersistenceException When an error occurs while persisting data.
     */
    void persistResumptionData(MavenProject rootProject, BuildResumptionData buildResumptionData)
            throws BuildResumptionPersistenceException;

    /**

                a = factory.createBuildArtifact("org.apache.maven", "h", "1.0", "jar");
                dependencies.add(a);
            } catch (Exception e) {
                throw new ArtifactMetadataRetrievalException("Error retrieving metadata", e, a);
            }
        }

        if ("i".equals(artifact.getArtifactId())) {
            Artifact a = null;
            try {

     *
     * @return The POM file or {@code null} if unknown.
     */
    File getPomFile();

    /**
     * Gets the project that was built.
     *
     * @return The project that was built or {@code null} if an error occurred and this result accompanies a
     *         {@link ProjectBuildingException}.
     */
    MavenProject getProject();

    /**
     * Gets the problems that were encountered during the project building.
     *

            for (ClassRealmManagerDelegate delegate : delegates) {
                try {
                    delegate.setupRealm(classRealm, request);
                } catch (Exception e) {
                    logger.error(
                            delegate.getClass().getName() + " failed to setup class realm " + classRealm + ": "
                                    + e.getMessage(),
                            e);
                }

     * @param message The message describing the problem, may be {@code null}.
     * @param severity The severity level of the problem, may be {@code null} to default to
     *            {@link org.apache.maven.building.Problem.Severity#ERROR}.
     * @param source A hint about the source of the problem like a file path, may be {@code null}.
     * @param lineNumber The one-based index of the line containing the problem or {@code -1} if unknown.

        List<Toolchain> toolchains = new ArrayList<>();

        if (models != null) {
            ToolchainFactory fact = factories.get(type);

            if (fact == null) {
                logger.error(
                        "Missing toolchain factory for type: " + type + ". Possibly caused by misconfigured project.");
            } else {
                for (ToolchainModel model : models) {
                    try {

        }

        String version = context.getSystemProperties().get("java.version");

        if (version == null || version.isEmpty()) {
            problems.add(
                    BuilderProblem.Severity.ERROR,
                    ModelProblem.Version.BASE,
                    "Failed to determine Java version for profile " + profile.getId(),
                    activation.getLocation("jdk"));
            return false;
        }