import java.util.*;
import java.util.stream.*;

class Main {
    public static void main(String[] args) {
        Set<String> s1 = new HashSet<>();
        s1.addAll(Arrays.asList("Apple", "Pear", "Orange", "Banana"));
        // elements can be in any order
        System.out.println("s1 = " + s1);
        
        Set<String> s2 = new TreeSet<>();
        s2.addAll(Arrays.asList("Apple", "Pear", "Orange", "Banana"));
        // elements are in a sorted order
        System.out.println("s2 = " + s2);
        
        Set<String> s3 = new LinkedHashSet<>();
        s3.addAll(Arrays.asList("Apple", "Pear", "Orange", "Banana"));
        // elements are in insertion order
        System.out.println("s3 = " + s3);
        
        Object[] strings = s3.toArray();
        for (Object item: strings) {
            System.out.println((String) item);
        }

        s3.removeAll(Arrays.asList("Pear", "Orange"));
        System.out.println("After removals, s3 = " + s3);
    }
}