JAVA - SETS

package datastructures;

import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.TreeSet;

public class Sets {

 public static void main(String[] args) {
  // hashset is random order
  Set animals = new HashSet();
  animals.add("dog");
  animals.add("pig");
  animals.add("hog");
  animals.add("cow");
  
  System.out.println(animals);
  
  animals.add("hog");
  animals.add("cow");
  animals.add("groose");
  // same elements does not add again
  System.out.println(animals);

  // linked hash set is same order in added
  Set animals1 = new LinkedHashSet();
  animals1.add("chicken");
  animals1.add("pig");
  animals1.add("snake");
  animals1.add("cow");
  
  System.out.println(animals1);
  
  // Difference of animals from animals1
  Set differenceSet = new HashSet(animals);
  differenceSet.removeAll(animals1);
  System.out.println(differenceSet);
  
  // Union of animals from animals1
  Set unionSet = new HashSet(animals);
  unionSet.addAll(animals1);
  System.out.println(unionSet);
    
  
  // tree set is in alphabetical order
  Set animals2 = new TreeSet();
  animals2.add("dog");
  animals2.add("pig");
  animals2.add("hog");
  animals2.add("cow");
  
  System.out.println(animals2);
 }

}

Here is the output:

[hog, cow, dog, pig]
[groose, hog, cow, dog, pig]
[chicken, pig, snake, cow]
[groose, hog, dog]
[groose, hog, chicken, snake, cow, dog, pig]
[cow, dog, hog, pig]