返回两个集合的交集元素而不修改Set

import java.util.HashSet;

import java.util.Set;

public class Main {
/**
* Returns the intersection of two sets without modifying the original sets.

*
* @param the type of objects contained in the sets
*
* @param first the first set
* @param second the second set
*
* @return the intersection of both sets
*/
public static Set intersection(Set first, Set second) {

    HashSet result = new HashSet(first);
    result.retainAll(second);
    return result;
}

}