Java 8 lambda to kotlin lambda

Question

public class Main {
    static class Account {
        private Long id;
        private String name;
        private Book book;

        public Account(Long id, String name, Book book) {
            this.id = id;
            this.name = name;
            this.book = book;
        }

        public String getName() {
            return name;
        }
    }
    public static void main(String[] args) {
        List<Account> data1 = new ArrayList<>();
        data1.add(new Account(1L,"name",null));
        List<String> collect = data1.stream().map(account -> account.getName()).collect(Collectors.toList());

        System.out.println(collect);
    }
}

In the above code I am trying to convert the following line

List<String> collect = data1.stream().map(account -> account.getName()).collect(Collectors.toList());

into kotlin code. Kotlin online editor gives me the following code

 val collect = data1.stream().map({ account-> account.getName() }).collect(Collectors.toList())
    println(collect)

which gives compilation error when i try to run it.

how to fix this???

or what is the kotlin way to get list of string from list of Account Object

Answer 1

Kotlin collections don't have a stream() method.

As mentioned in https://youtrack.jetbrains.com/issue/KT-5175, you can use

(data1 as java.util.Collection<Account>).stream()...

or you can use one of the native Kotlin alternatives that don't use streams, listed in the answers to this question:

val list = data1.map { it.name }