results.add(result2);

        ProjectBuildingException exception = new ProjectBuildingException(results);
        String message = exception.getMessage();

        assertTrue(
                message.contains("3 problems were encountered while processing the POMs (2 errors)"),
                "Message should contain problem count and error count");

     */
    public ToolchainsBuildingException(List<Problem> problems) {
        super(toMessage(problems));

        this.problems = new ArrayList<>();
        if (problems != null) {
            this.problems.addAll(problems);
        }
    }

    /**
     * Gets the problems that caused this exception.
     *
     * @return The problems that caused this exception, never {@code null}.
     */

        }

        return toolchains;
    }

    private boolean hasErrors(List<Problem> problems) {
        if (problems != null) {
            for (Problem problem : problems) {
                if (Problem.Severity.ERROR.compareTo(problem.getSeverity()) >= 0) {
                    return true;
                }
            }
        }

        return false;
    }

     * @param problems the collection of problems to include in the message
     * @return a formatted message including details of all problems
     */
    protected static String buildMessage(String message, ProblemCollector<BuilderProblem> problems) {
        StringBuilder msg = new StringBuilder(message);
        problems.problems().forEach(problem -> msg.append("\n * ")
                .append(problem.getSeverity().name())

     */
    public static <T> Result<T> newResult(T model, Iterable<? extends ModelProblem> problems) {
        return new Result<>(hasErrors(problems), model, problems);
    }

    /**
     * New result consisting of given result and new problem. Convenience for newResult(result.get(),
     * concat(result.getProblems(),problems)).
     *
     * @param result
     * @param problem
     */

     *
     * @param severity the severity level to get problems for
     * @return a stream of problems with the specified severity
     */
    @Nonnull
    Stream<P> problems(BuilderProblem.Severity severity);

    /**
     * Creates an "empty" problem collector that doesn't store any problems.
     *
     * @param <P> the type of problem
     * @return an empty problem collector
     */
    @Nonnull

        return null;
    }

    static String toMessage(String modelId, List<ModelProblem> problems) {
        StringWriter buffer = new StringWriter(1024);

        PrintWriter writer = new PrintWriter(buffer);

        writer.print(problems.size());
        writer.print((problems.size() == 1) ? " problem was " : " problems were ");
        writer.print("encountered while building the effective model");

    private List<Problem> problems;

    /**
     * Default constructor
     *
     * @param effectiveToolchains the merged toolchains, may not be {@code null}
     * @param problems the problems while building the effectiveToolchains, if any.
     */
    public DefaultToolchainsBuildingResult(PersistedToolchains effectiveToolchains, List<Problem> problems) {
        this.effectiveToolchains = effectiveToolchains;

        }

        if (hasErrors(problems.getProblems())) {
            throw new SettingsBuildingException(problems.getProblems());
        }

        return new DefaultSettingsBuildingResult(userSettings, problems.getProblems());
    }

    private boolean hasErrors(List<SettingsProblem> problems) {
        if (problems != null) {
            for (SettingsProblem problem : problems) {

        this.problems = (problems != null) ? problems : new ArrayList<>();
    }

    public List<SettingsProblem> getProblems() {
        return problems;
    }

    public void setSource(String source) {
        this.source = source;
    }

    @Override
    public void add(SettingsProblem.Severity severity, String message, int line, int column, Exception cause) {