class NullabilityBreakingChangesRule extends AbstractGradleViolationRule {

    enum Nullability {
        NON_NULL, NULLABLE, UNMARKED,
    }

    private static final List<String> NULLABLE_ANNOTATIONS = [
        javax.annotation.Nullable,
        org.jetbrains.annotations.Nullable,
        org.jspecify.annotations.Nullable,
    ].collect { it.name }

                "Method com.example.Source.baz(java.lang.String): Return nullability changed from null-unmarked to non-nullable",
            )
            assertHasNoInformation()
        }
    }

    @Test
    fun `from null-unmarked returning to nullable returning is breaking`() {

        checkNotBinaryCompatibleJava(
            v1 = """

 */
package org.apache.maven.api.cli;

import java.util.List;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

/**
 * Defines a simple logging interface for Maven CLI operations. These operations happen "early", when there may

     */
    public InvokerException(@Nullable String message) {
        super(message);
    }

    /**
     * Constructs a new {@code InvokerException} with the specified detail message and cause.
     *
     * @param message the detail message explaining the cause of the exception
     * @param cause the underlying cause of the exception
     */
    public InvokerException(@Nullable String message, @Nullable Throwable cause) {

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.cli.transfer;

import java.io.File;

import org.apache.maven.api.annotations.Nullable;
import org.eclipse.aether.transfer.TransferResource;

/**
 * Immutable identifier of a {@link TransferResource}.

            DefaultDependencyResolverRequest(
                    @Nonnull Session session,
                    @Nullable RequestTrace trace,
                    @Nonnull RequestType requestType,
                    @Nullable Project project,
                    @Nullable Artifact rootArtifact,
                    @Nullable DependencyCoordinates root,
                    @Nonnull Collection<DependencyCoordinates> dependencies,

    Callable<@Nullable Void> cancelRunnable =
        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() {
            cancellationSuccess.set(currentFuture.get().cancel(true));
            awaitUnchecked(barrier);
            return null;
          }
        };
    Callable<@Nullable Void> setFutureCompleteSuccessfullyRunnable =

  }

  /**
   * Class for testing all permutations of nullable/non-nullable two-argument methods using
   * testMethod().
   *
   * <ul>
   *   <li>normalNormal: two params, neither is Nullable
   *   <li>nullableNormal: only first param is Nullable
   *   <li>normalNullable: only second param is Nullable
   *   <li>nullableNullable: both params are Nullable
   * </ul>
   */
  public static class TwoArg {

   *
   * <p>The serialized output consists of the number of entries, first key, first value, second key,
   * second value, and so on.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMap(
      Map<K, V> map, ObjectOutputStream stream) throws IOException {
    stream.writeInt(map.size());
    for (Map.Entry<K, V> entry : map.entrySet()) {

  public void testTransformEntrySetContains() {
    Map<@Nullable String, @Nullable Boolean> underlying = new HashMap<>();
    underlying.put("a", null);
    underlying.put("b", true);
    underlying.put(null, true);

    Map<@Nullable String, @Nullable Boolean> map =
        transformValues(
            underlying,
            new Function<@Nullable Boolean, @Nullable Boolean>() {
              @Override