Java 8 List into Map

Question

I want to translate a List of objects into a Map using Java 8\'s streams and lambdas.

This is how I would write it in Java 7 and below.

private Map&l         


        

Answer 1

If every new value for the same key name has to be overridden:

public Map < String, Choice > convertListToMap(List < Choice > choices) {
    return choices.stream()
        .collect(Collectors.toMap(Choice::getName,
            Function.identity(),
            (oldValue, newValue) - > newValue));
}

If all choices have to be grouped in a list for a name:

public Map < String, Choice > convertListToMap(List < Choice > choices) {
    return choices.stream().collect(Collectors.groupingBy(Choice::getName));
}