this.extension = (extension != null && !extension.isEmpty()) ? extension : null;
        this.version = (version != null && !version.isEmpty()) ? version : null;
        this.message = (message != null && !message.isEmpty()) ? message : null;
    }

    @Override
    public String getGroupId() {
        if (groupId != null) {
            return groupId;
        } else {
            return artifact.getGroupId();

    public void add(BuilderProblem.Severity severity, ModelProblem.Version version, String message) {
        add(severity, version, message, null, null);
    }

    @Override
    public void add(
            BuilderProblem.Severity severity, ModelProblem.Version version, String message, InputLocation location) {
        add(severity, version, message, location, null);
    }

    @Override
    public void add(

    /**
     * @param message the message to give
     * @param e the {@link Exception}
     */
    public ToolchainsBuilderException(String message, Exception e) {
        super(message, e);
        this.problems = List.of();
    }

    public ToolchainsBuilderException(String message, List<BuilderProblem> problems) {

    public static String getMessage(Exception e) {
        String message = e.getMessage();
        if (e instanceof XMLStreamException xe && xe.getLocation() != null) {
            int idx = message.indexOf("\nMessage: ");
            if (idx >= 0) {
                return message.substring(idx + "\nMessage: ".length());
            }
        }
        return message;
    }

    public StaxLocation(javax.xml.stream.Location location) {

            if (cause instanceof ModelBuildingException) {
                String message = "In: " + pom + "\n\n";
                for (ModelProblem problem : ((ModelBuildingException) cause).getProblems()) {
                    message += problem + "\n";
                }
                System.out.println(message);
            }

            throw e;
        }
    }

 * The default implementation will look for a {@code .mvn} child directory
 * or a {@code pom.xml} containing the {@code root="true"} attribute.
 */
public interface RootLocator {

    String UNABLE_TO_FIND_ROOT_PROJECT_MESSAGE = "Unable to find the root directory. "
            + "Create a .mvn directory in the root directory or add the root=\"true\""
            + " attribute on the root project's model to identify it.";

    @Nonnull

    private static boolean validateStringEmpty(
            List<BuilderProblem> problems, String fieldName, String string, String message) {
        if (string == null || string.length() == 0) {
            return true;
        }

        addViolation(problems, BuilderProblem.Severity.WARNING, fieldName, null, message);

        return false;
    }

    /**
     * Asserts:
     * <p/>
     * <ul>

        DefaultSession session =
                new DefaultSession(ms, mock(RepositorySystem.class), Collections.emptyList(), null, null, null);

        assertEquals(
                RootLocator.UNABLE_TO_FIND_ROOT_PROJECT_MESSAGE,
                assertThrows(IllegalStateException.class, session::getRootDirectory)
                        .getMessage());
    }

    @Test
    void testRootDirectory() {

LogFactory.getInstance(String name). Your application can contain references to multiple loggers that are used for different purposes. A typical scenario for a server application is to have each major component of the server use its own Log instance. Cause messages to be logged (if the corresponding detail level is enabled) by calling appropriate methods (trace(), debug(), info(), warn(), error, and fatal()). For convenience, LogFactory also offers a static method getLog() that combines the typical two-step...

    private final String modelId;

    private final String message;

    private final Exception exception;

    private final Severity severity;

    private final Version version;

    /**
     * Creates a new problem with the specified message and exception.
     *
     * @param message The message describing the problem, may be {@code null}.