Efficient intersection of two List in Java?

Question

Question is simple:

I have two List

List columnsOld = DBUtils.GetColumns(db, TableName);
List columnsNew = DBUtils.GetCol         


        

Answer 1

How about

private List intersect(List A, List B) {
    List rtnList = new LinkedList<>();
    for(String dto : A) {
        if(B.contains(dto)) {
            rtnList.add(dto);
        }
    }
    return rtnList;
}