* requireNonNull(top.next())`) once our checker supports it.
             *
             * (The problem is likely
             * https://github.com/jspecify/jspecify-reference-checker/blob/61aafa4ae52594830cfc2d61c8b113009dbdb045/src/main/java/com/google/jspecify/nullness/NullSpecAnnotatedTypeFactory.java#L896)
             */
            requireNonNull(element);
            if (visited.add(element)) {
              return element;

				<include name="dataformat/stax-api-*" />
				<include name="dataformat/xmlbeans-*" />
				<include name="minhash/guava-*" />
				<include name="minhash/failureaccess-*" />
				<include name="minhash/jspecify-*" />
				<include name="minhash/listenablefuture-*" />
			</fileset>
		</delete>
	</target>

After migrating to Java 8, we can use pluggable type checkers to ensure that our annotations are consistent, 
and there are no missing null checks.

## Decision

Use "NullAway" in JSpecify mode to check for null-related errors in Java code.

Consider improper uses of `null` detected by NullAway a compilation error (not a warning, and not a separate CI job to test).

  </properties>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.jspecify</groupId>
        <artifactId>jspecify</artifactId>
        <version>${jspecify.version}</version>
      </dependency>
      <dependency>
        <groupId>com.google.errorprone</groupId>
        <artifactId>error_prone_annotations</artifactId>

				</exclusion>
				<exclusion>
					<groupId>com.google.errorprone</groupId>
					<artifactId>error_prone_annotations</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.jspecify</groupId>
					<artifactId>jspecify</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>com.google.oauth-client</groupId>
			<artifactId>google-oauth-client</artifactId>

import com.google.common.annotations.GwtCompatible;
import java.util.AbstractCollection;
import java.util.Collection;
import java.util.Iterator;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A simplistic collection which implements only the bare minimum allowed by the spec, and throws
 * exceptions whenever it can.
 *

 */

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import com.google.common.util.concurrent.AbstractFuture.TrustedFuture;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link AbstractFuture} that use a {@link TrustedFuture} for {@link
 * AbstractFuture#setFuture} calls.
 */
@GwtCompatible
@NullUnmarked

 */

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import com.google.common.util.concurrent.AbstractFuture.TrustedFuture;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link AbstractFuture} that use a non-{@link TrustedFuture} for {@link
 * AbstractFuture#setFuture} calls.
 */
@GwtCompatible
@NullUnmarked

import com.google.common.annotations.GwtCompatible;
import java.util.AbstractCollection;
import java.util.Collection;
import java.util.Iterator;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A simplistic collection which implements only the bare minimum allowed by the spec, and throws
 * exceptions whenever it can.
 *

 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Collections;
import java.util.Iterator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A utility for testing an Iterator implementation by comparing its behavior to that of a "known