private final ConcurrentMap<BuilderProblem.Severity, LongAdder> counters;
        private final ConcurrentMap<BuilderProblem.Severity, List<P>> problems;
        private final Predicate<? super P> filter;

        private static final List<BuilderProblem.Severity> REVERSED_ORDER = Arrays.stream(
                        BuilderProblem.Severity.values())
                .sorted(Comparator.reverseOrder())

/**
 * Base class for all maven exceptions carrying {@link BuilderProblem}s.
 *
 * @since 4.0.0
 */
@Experimental
public abstract class MavenBuilderException extends MavenException {

    /**
     * The collection of problems associated with this exception.
     */
    private final ProblemCollector<BuilderProblem> problems;

    /**

                @Nonnull
                @Override
                public Collection<BuilderProblem> getProblems() {
                    return new MappedCollection<>(res.getProblems(), this::toProblem);
                }

                private BuilderProblem toProblem(ModelProblem problem) {
                    return new BuilderProblem() {
                        @Override
                        public String getSource() {

     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link SettingsBuilderException}.
     *
     * @return the problems that were encountered during the settings building, can be empty but never {@code null}
     */
    @Nonnull
    ProblemCollector<BuilderProblem> getProblems();

     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link ToolchainsBuilderException}.
     *
     * @return the problems that were encountered during the settings building, can be empty but never {@code null}
     */
    @Nonnull
    ProblemCollector<BuilderProblem> getProblems();

     *
     * @param settings The settings to validate, must not be {@code null}.
     * @return The list of problems that were encountered, must not be {@code null}.
     */
    @Nonnull
    default ProblemCollector<BuilderProblem> validate(@Nonnull Settings settings) {
        return validate(settings, false);
    }

    /**
     * Validate the specified settings.
     *

     */
    public ToolchainsBuilderException(String message, Exception e) {
        super(message, e);
    }

    public ToolchainsBuilderException(String message, ProblemCollector<BuilderProblem> problems) {
        super(message, problems);
    }

     * @param e the {@link Exception}
     */
    public SettingsBuilderException(String message, Exception e) {
        super(message, e);
    }

    public SettingsBuilderException(String message, ProblemCollector<BuilderProblem> problems) {
        super(message, problems);
    }

     *
     * @return the problems that were encountered during the project building, can be empty but never {@code null}
     */
    @Nonnull
    Collection<BuilderProblem> getProblems();

    /**
     * Gets the result of the dependency resolution for the project.
     *
     * @return the result of the dependency resolution for the project
     */
    @Nonnull

 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 */
public interface ModelProblem extends BuilderProblem {

    /**
     * Enumeration of model versions that can be validated.
     * These versions correspond to different levels of validation that can be applied
     * during model building, based on the POM schema version.