tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

import org.jspecify.annotations.Nullable;

/**
 * Provides static methods for serializing collection classes.
 *
 * <p>This class assists the implementation of collection classes. Do not use this class to
 * serialize collections that are defined elsewhere.
 *
 * @author Jared Levy
 */
@GwtIncompatible
@J2ktIncompatible
final class Serialization {
  private Serialization() {}

  /**

        }
    }

    // Test class that causes NullPointerException
    private static class NullPointerScoreBooster extends ScoreBooster {
        @Override
        public long process() {
            // This will cause NullPointerException when auto-unboxing
            Long nullValue = null;
            return nullValue;
        }
    }

    // Test class that throws RuntimeException

import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Map;
import java.util.Set;

/**
 * Optional features of classes derived from {@code Map}.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum MapFeature implements Feature<Map> {

//// tab | Python 3.8+

* `List`
* `Tuple`
* `Set`
* `Dict`
* `Union`
* `Optional`
* ...and others.

////

### Classes as types { #classes-as-types }

You can also declare a class as the type of a variable.

Let's say you have a class `Person`, with a name:

{* ../../docs_src/python_types/tutorial010.py hl[1:3] *}

Then you can declare a variable to be of type `Person`:

  public void testPropagateIfPossible_twoDeclared_firstSame() {
    assertThrows(
        SomeCheckedException.class,
        () ->
            propagateIfPossible(
                new SomeCheckedException(),
                SomeCheckedException.class,
                SomeOtherCheckedException.class));
  }

  @J2ktIncompatible
  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)

    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

/**
 * A future that, if it fails, may <i>optionally</i> provide access to the cause of the failure.
 *
 * <p>This class is used only for micro-optimization. Standard {@code Future} utilities benefit from
 * this optimization, so there is no need to specialize methods to return or accept this type
 * instead of {@code ListenableFuture}.
 *
 * <p>This class is GWT-compatible.
 *

    class HappyPath {
        @Test
        void acceptWithMockedFile() throws Exception {
            SmbFile mockFile = mock(SmbFile.class);
            when(mockFile.getPath()).thenReturn("/share/file.txt");
            assertTrue(ALWAYSACTIVE.accept(mockFile));
        }
    }

    @Nested
    @DisplayName("Invalid input – null file handling")
    class InvalidPath {
        @Test

import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Map;
import java.util.Set;

/**
 * Optional features of classes derived from {@code Map}.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum MapFeature implements Feature<Map> {