Добрый день!
Посмотрите пожалуйста, и объясните в чем разница между
public static Set<Cat> createCats() {
HashSet<Cat> result = new HashSet<Cat>();
result.add(new Cat());
result.add(new Cat());
result.add(new Cat());
result.add(new Cat());
return result;
}
public static Set<Dog> createDogs() {
HashSet<Dog> result = new HashSet<Dog>();
Dog dog = new Dog();
result.add(dog);
result.add(dog);
result.add(dog);
return result;
}package com.javarush.task.task08.task0820;
import java.util.HashSet;
import java.util.Set;
/*
Множество всех животных
*/
public class Solution {
public static void main(String[] args) {
Set<Cat> cats = createCats();
Set<Dog> dogs = createDogs();
Set<Object> pets = join(cats, dogs);
printPets(pets);
removeCats(pets, cats);
printPets(pets);
}
public static Set<Cat> createCats() {
HashSet<Cat> result = new HashSet<Cat>();
result.add(new Cat());
result.add(new Cat());
result.add(new Cat());
result.add(new Cat());
return result;
}
public static Set<Dog> createDogs() {
HashSet<Dog> result = new HashSet<Dog>();
Dog dog = new Dog();
result.add(dog);
result.add(dog);
result.add(dog);
return result;
}
public static Set<Object> join(Set<Cat> cats, Set<Dog> dogs) {
Set<Object> join = new HashSet<>();
join.addAll(dogs);
join.addAll(cats);
return join;
}
public static void removeCats(Set<Object> pets, Set<Cat> cats) {
pets.removeAll(cats);
}
public static void printPets(Set<Object> pets) {
for (Object text : pets)
{
System.out.println(text);
}
}
public static class Cat {
}
public static class Dog {
}
}