Set

package set;

import java.util.*;


public interface Set<E> extends Collection<E> {
    // Query Operations

    int size();

    boolean isEmpty();

    boolean contains(Object o);

    Iterator<E> iterator();

    Object[] toArray();

    <T> T[] toArray(T[] a);


    // Modification Operations

    boolean add(E e);


    boolean remove(Object o);


    // Bulk Operations

    boolean containsAll(Collection<?> c);

    boolean addAll(Collection<? extends E> c);

    boolean retainAll(Collection<?> c);

    boolean removeAll(Collection<?> c);

    void clear();


    // Comparison and hashing

    boolean equals(Object o);

    int hashCode();

    @Override
    default Spliterator<E> spliterator() {
        return Spliterators.spliterator(this, Spliterator.DISTINCT);
    }
}