assertEquals(2, collector.getProblems().size());

        Problem p1 = collector.getProblems().get(0);
        assertEquals(Severity.ERROR, p1.getSeverity());
        assertEquals("MESSAGE1", p1.getMessage());
        assertEquals(-1, p1.getLineNumber());
        assertEquals(-1, p1.getColumnNumber());
        assertNull(p1.getException());

        Problem p2 = collector.getProblems().get(1);

import org.apache.maven.api.services.BuilderProblem;

/**
 * Describes a problem that was encountered during settings building. A problem can either be an exception that was
 * thrown or a simple string message. In addition, a problem carries a hint about its source, e.g. the settings file
 * that exhibits the problem.
 */
class DefaultBuilderProblem implements BuilderProblem {
    final String source;

### Suggest solutions

* After being able to understand the question, you can give them a possible **answer**.

* In many cases, it's better to understand their **underlying problem or use case**, because there might be a better way to solve it than what they are trying to do.

    @Test
    void testNewInstance() {
        ProblemCollector collector1 = ProblemCollectorFactory.newInstance(null);

        Problem problem = new DefaultProblem("MESSAGE1", null, null, -1, -1, null);
        ProblemCollector collector2 = ProblemCollectorFactory.newInstance(Collections.singletonList(problem));

        assertNotSame(collector1, collector2);
        assertEquals(0, collector1.getProblems().size());

                        result.getProject().getId());

                for (ModelProblem problem : result.getProblems()) {
                    String loc = ModelProblemUtils.formatLocation(problem, result.getProjectId());
                    LOGGER.warn("{}{}", problem.getMessage(), ((loc != null && !loc.isEmpty()) ? " @ " + loc : ""));
                }

                problems = true;
            }

  return when {
    // If there was a protocol problem, don't recover.
    e is ProtocolException -> false

    // If there was an interruption or timeout (SocketTimeoutException), don't recover.
    // For the socket connect timeout case we do not try the same host with a different
    // ConnectionSpec: we assume it is unreachable.
    e is InterruptedIOException -> false

    /**
     * New result consisting of given result and new problem. Convenience for newResult(result.get(),
     * concat(result.getProblems(),problems)).
     *
     * @param result
     * @param problem
     */
    public static <T> Result<T> addProblem(Result<T> result, ModelProblem problem) {
        return addProblems(result, Collections.singleton(problem));
    }

    /**
     * New result that includes the given

                        return defaultModelBuilder.readRawModel(gaBuildingRequest, problems);
                    } catch (ModelBuilderException e) {
                        // gathered with problem collector
                    }
                }
                return null;
            }

            private void loadFullReactor() {
                if (!fullReactorLoaded) {

        Provide a [minimal, self-contained example](https://en.wikipedia.org/wiki/Minimal_reproducible_example) project demonstrating the problem as a GitHub repository or an attached archive.
        You can use [the template](https://github.com/gradle/gradle-issue-reproducer) with a Gradle GitHub action set up to showcase your problem.
        In the rare cases where this is infeasible, we will also accept a detailed set of instructions.

  }

  private static class StringWrapper {
    private final String value;

    public StringWrapper(String value) {
      this.value = value;
    }
  }

  @GwtIncompatible // J2CL generics problem
  public void testAndThen() {
    Converter<StringWrapper, String> first =
        new Converter<StringWrapper, String>() {
          @Override
          protected String doForward(StringWrapper object) {