@Override
      public void onOpen(@NotNull EventSource eventSource, @NotNull Response response) {
        try {
          assertEquals("text/event-stream", response.request().header("Accept"));
        } catch (Exception e) {
          future.completeExceptionally(e);
        }
      }

      @Override

  }

  public void testNotNull_apply() {
    Predicate<@Nullable Integer> notNull = Predicates.notNull();
    assertFalse(notNull.apply(null));
    assertTrue(notNull.apply(1));
  }

  public void testNotNull_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.notNull(), Predicates.notNull())
        .addEqualityGroup(Predicates.isNull())
        .testEquals();
  }

        MultiValidationBean bean = new MultiValidationBean();
        bean.setRequiredCron(null); // Violates NotNull

        Set<ConstraintViolation<MultiValidationBean>> violations = validator.validate(bean);
        assertEquals(1, violations.size()); // Only NotNull violation

        bean.setRequiredCron("invalid"); // Now violates CronExpression
        violations = validator.validate(bean);

        return "Predicates.isNull()";
      }
    },
    /**
     * @see Predicates#notNull()
     */
    NOT_NULL {
      @Override
      public boolean apply(@Nullable Object o) {
        return o != null;
      }

      @Override
      public String toString() {
        return "Predicates.notNull()";
      }
    };

    @SuppressWarnings("unchecked") // safe contravariant cast

        assertEquals("{constraints.Max.message}", FessMessages.CONSTRAINTS_Max_MESSAGE);
        assertEquals("{constraints.Min.message}", FessMessages.CONSTRAINTS_Min_MESSAGE);
        assertEquals("{constraints.NotNull.message}", FessMessages.CONSTRAINTS_NotNull_MESSAGE);
        assertEquals("{constraints.Null.message}", FessMessages.CONSTRAINTS_Null_MESSAGE);
        assertEquals("{constraints.Past.message}", FessMessages.CONSTRAINTS_Past_MESSAGE);

      Map<Class<? extends @NonNull B>, B> backingMap) {
    return new MutableClassToInstanceMap<>(backingMap);
  }

  private final Map<Class<? extends @NonNull B>, B> delegate;

  private MutableClassToInstanceMap(Map<Class<? extends @NonNull B>, B> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  protected Map<Class<? extends @NonNull B>, B> delegate() {
    return delegate;
  }

   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(predicate).findFirst()}.
   */
  public final Optional<@NonNull E> firstMatch(Predicate<? super E> predicate) {
    // Unsafe, but we can't do much about it now.
    return Iterables.<@NonNull E>tryFind((Iterable<@NonNull E>) getDelegate(), predicate);
  }

  /**
   * Returns a fluent iterable that applies {@code function} to each element of this fluent

   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(predicate).findFirst()}.
   */
  public final Optional<@NonNull E> firstMatch(Predicate<? super E> predicate) {
    // Unsafe, but we can't do much about it now.
    return Iterables.<@NonNull E>tryFind((Iterable<@NonNull E>) getDelegate(), predicate);
  }

  /**
   * Returns a fluent iterable that applies {@code function} to each element of this fluent

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to object arrays.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to object arrays.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible