Generic Method의 사용

# Main.java

import java.util.Arrays;

import java.util.HashSet;

import java.util.Set;

public class Main {

    

    public static <E> Set<E> union(Set<E> s1, Set<E> s2) {

Set<E> result = new HashSet<>(s1);

result.addAll(s2);

return result;

    } 

    public static void main(String[] args) {

Set<String> guys = new HashSet<>(Arrays.asList("Tom", "Dick", "Harry"));

Set<String> numbers = new HashSet<>(Arrays.asList("1", "2", "3"));

Set<String> mix = union(guys, numbers);

System.out.println(mix);

    }

}

# 결과

[1, 2, Tom, 3, Harry, Dick]