import java.util.NoSuchElementException;
import java.util.Set;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.function.Consumer;
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.
 *

import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.function.BiFunction;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An implementation of {@code RangeMap} based on a {@code TreeMap}, supporting all optional
 * operations.
 *

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit test for {@link Booleans}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault

import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Spliterator;
import java.util.function.Consumer;
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.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests representing the contract of {@link Map}. Concrete subclasses of this base class test
 * conformance of concrete {@link Map} subclasses to that contract.
 *

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

/**
 * A {@link BiMap} backed by two hash tables. This implementation allows null keys and values. A
 * {@code HashBiMap} and its inverse are both serializable.
 *

import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A double-ended priority queue, which provides constant-time access to both its least element and

import java.util.List;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * This class contains static utility methods that operate on or return objects of type {@link

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

/**
 * A multiset which maintains the ordering of its elements, according to either their natural order
 * or an explicit {@link Comparator}. In all cases, this implementation uses {@link

import java.util.TreeSet;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.regex.Pattern;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Generates fresh instances of types that are different from each other (if possible).
 *
 * @author Ben Yu
 */
@GwtIncompatible
@J2ktIncompatible