// when it is present, and for others we must omit it!
        // https://tools.ietf.org/html/rfc4055#section-2.1
        ObjectIdentifiers.SHA256_WITH_RSA_ENCRYPTION -> Adapters.NULL
        ObjectIdentifiers.RSA_ENCRYPTION -> Adapters.NULL
        ObjectIdentifiers.EC_PUBLIC_KEY -> Adapters.OBJECT_IDENTIFIER
        else -> null
      }
    }

  /**
   * ```

    checkNotNull(updaterFunction);
    Long result =
        map.compute(
            key,
            (k, value) -> updaterFunction.applyAsLong((value == null) ? 0L : value.longValue()));
    return requireNonNull(result);
  }

  /**
   * Updates the value currently associated with {@code key} with the specified function, and

    List<@Nullable String> list = newArrayList("a", null, "b", null, "a", null);
    assertEquals(2, frequency(list.iterator(), "a"));
    assertEquals(1, frequency(list.iterator(), "b"));
    assertEquals(0, frequency(list.iterator(), "c"));
    assertEquals(0, frequency(list.iterator(), 4.2));
    assertEquals(3, frequency(list.iterator(), null));
  }

  @GwtIncompatible // slow (~4s)

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic set which implements the bare minimum so that it can be used in tests without
 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they
 * can be used in the testers.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

                        {
                            "required": False,
                            "schema": IsDict(
                                {
                                    "anyOf": [{"type": "string"}, {"type": "null"}],
                                    "title": "Q",
                                }
                            )
                            | IsDict(

				}
				return buf.length;
			},
			write(fd, buf, offset, length, position, callback) {
				if (offset !== 0 || length !== buf.length || position !== null) {
					callback(enosys());
					return;
				}
				const n = this.writeSync(fd, buf);
				callback(null, n);
			},
			chmod(path, mode, callback) { callback(enosys()); },
			chown(path, uid, gid, callback) { callback(enosys()); },

    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  public void testEquals_null() {
    // noinspection ObjectEqualsNull
    assertFalse("An object should not be equal to null.", collection.equals(null));
  }

  public void testEquals_notACollection() {
    // noinspection EqualsBetweenInconvertibleTypes
    assertFalse(
        "A Collection should never equal an object that is not a Collection.",

        srvsvc.ShareInfo502 info502 = (srvsvc.ShareInfo502)info;
        if (info502.security_descriptor != null) {
            SecurityDescriptor sd;
            sd = new SecurityDescriptor(info502.security_descriptor, 0, info502.sd_size);
            return sd.aces;
        }
        return null;
    }

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * The annotated element must not be null.
 * <p>
 * Annotated fields must not be null after construction has completed.
 * <p>
 * When this annotation is applied to a method it applies to the method return value.
 *
 * @see Nullable
 * @since 4.0.0
 */
@Experimental

    /**
     * Builds the effective toolchains of the specified toolchains files.
     *
     * @param request The toolchains building request that holds the parameters, must not be {@code null}.
     * @return The result of the toolchains building, never {@code null}.
     * @throws ToolchainsBuildingException If the effective toolchains could not be built.
     */