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 nameMap(List choices) { final Map hashMap = new HashMap<>(); for (final Choice choice : choices) { hashMap.put(choice.getName(), choice); } return hashMap; } ``` I can accomplish this easily using Java 8 and Guava but I would like to know how to do this without Guava. In Guava: ``` private Map nameMap(List choices) { return Maps.uniqueIndex(choices, new Function() { @Override public String apply(final Choice input) { return input.getName(); } }); } ``` And Guava with Java 8 lambdas. ``` private Map nameMap(List choices) { return Maps.uniqueIndex(choices, Choice::getName); } ```

Accepted Answer

Based on `Collectors` documentation it's as simple as:

```
Map<String, Choice> result =
    choices.stream().collect(Collectors.toMap(Choice::getName,
                                              Function.identity()));
```

Java 8 List<V> into Map<K, V>

Solution

Problem

Related problems