MultiValueMap ( org.apache.commons.collections )

package de.eknori.test;
 
import org.apache.commons.collections.map.MultiValueMap;
 
public class MultiMap {
 
	public static void main(String[] args) {
 
		MultiValueMap superheroes = new MultiValueMap();
		String key = "human";
		superheroes.put("mutant", "Wolverine");
		superheroes.put("mutant", "Beast");
		superheroes.put("alien", "Superman");
		superheroes.put("human", "Batman");
		superheroes.put("human", "Captain America");
 
		System.out.println(key + " superheroes: " + superheroes.get(key));
		System.out.println("There are " + superheroes.size()
				+ " different kind of superheroes: " + superheroes.keySet());
 
		System.out.println("All superheroes: " + superheroes.values());
	}
}