import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Provides static methods for working with {@code Collection} instances.
 *
 * <p><b>Java 8+ users:</b> several common uses for this class are now more comprehensively

import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Supplies an arbitrary "default" instance for a wide range of types, often useful in testing
 * utilities.
 *

import com.google.common.collect.testing.features.MapFeature;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Tester for {@link Multimap#put}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

import com.google.common.collect.testing.features.CollectionSize;
import java.lang.reflect.Method;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests addAll operations on a collection. Can't be invoked directly;

import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ArrayList;
import java.util.List;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tester for equals() and hashCode() methods of a class.
 *
 * <p>The simplest use case is:
 *
 * <pre>
 * new EqualsTester().addEqualityGroup(foo).testEquals();
 * </pre>
 *

import com.google.common.collect.testing.features.MapFeature;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Tester for {@link Multimap#put}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

import java.util.Collection;
import java.util.Comparator;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@code SetMultimap} whose set of values for a given key are kept sorted; that is, they comprise
 * a {@link SortedSet}. It cannot hold duplicate key-value pairs; adding a key-value pair that's

import com.google.common.primitives.Booleans;
import java.util.Comparator;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit test for {@link ComparisonChain}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class ComparisonChainTest extends TestCase {

import com.google.common.testing.NullPointerTester;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit test for {@link Optional}.
 *
 * @author Kurt Alfred Kluever
 */
@ElementTypesAreNonnullByDefault
@GwtCompatible(emulated = true)

import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * CompactHashSet is an implementation of a Set. All optional operations (adding and removing) are
 * supported. The elements can be any objects.
 *