rspec/rules/S2203/java/rule.adoc

== Why is this an issue?

While you can use either ``++forEach(list::add)++`` or ``++collect++`` with a ``++Stream++``, ``++collect++`` is by far the better choice because it's automatically thread-safe and parallellizable. 


=== Noncompliant code example

[source,java]
----
List<String> bookNames = new ArrayList<>();
books.stream().filter(book -> book.getIsbn().startsWith("0"))
                .map(Book::getTitle)
                .forEach(bookNames::add);  // Noncompliant
----


=== Compliant solution

[source,java]
----
List<String> bookNames = books.stream().filter(book -> book.getIsbn().startsWith("0"))
                .map(Book::getTitle)
                .collect(Collectors.toList());
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Use "collect(Collectors.toList())" instead of "forEach(xxx)".


endif::env-github,rspecator-view[]