Convert String array to Map using Java 8 Lambda expressions

You can modify your solution to collect the Stream of String arrays into a Map (instead of using forEach) :

Map<String, Double> kvs =
    Arrays.asList("a:1.0", "b:2.0", "c:3.0")
        .stream()
        .map(elem -> elem.split(":"))
        .collect(Collectors.toMap(e -> e[0], e -> Double.parseDouble(e[1])));

Of course this solution has no protection against invalid input. Perhaps you should add a filter just in case the split String has no separator :

Map<String, Double> kvs =
    Arrays.asList("a:1.0", "b:2.0", "c:3.0")
        .stream()
        .map(elem -> elem.split(":"))
        .filter(elem -> elem.length==2)
        .collect(Collectors.toMap(e -> e[0], e -> Double.parseDouble(e[1])));

This still doesn't protect you against all invalid inputs (for example "c:3r" would cause NumberFormatException to be thrown by parseDouble).