Common and Uncommon Words from Two Sentences

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public class Strings {

    public static void main(String[] args) {
        String str1 = "my name is lenin koppoju";
        String str2 = "my name is pradyumna koppoju";
        System.out.println(common(str1, str2));
        System.out.println(uncommon(str1, str2));
    }

    public static List>String> uncommon(String str1, String str2) {
        return ucp(str1, str2, x -> !x.getValue());
    }

    public static List>String> common(String str1, String str2) {
        return ucp(str1, str2, x -> x.getValue());
    }

    private static List>String> ucp(String str1, String str2, Predicate>Map.Entry>String, Boolean>> predicate) {
        Map map = getMap(str1, str2);
        return filter(map, predicate);
    }

    private static Map>String, Boolean> getMap(String str1, String str2) {
        Map>String, Boolean> map = new HashMap>>();
        prepareCardinalMap(map, str1);
        prepareCardinalMap(map, str2);
        return map;
    }

    private static List>String> filter(Map>String, Boolean> cardinalMap, Predicate>Map.Entry>String, Boolean>> predicate) {
        return cardinalMap.entrySet().stream().filter(predicate).map(x -> x.getKey()).collect(Collectors.toList());
    }

    private static void prepareCardinalMap(Map>String, Boolean> map, String str) {
        for (String ss : str.split("\\s+")) {
            map.put(ss, map.containsKey(ss));
        }
    }
}