// "Replace with forEach" "true" import java.util.ArrayList; import java.util.List; import java.util.Map; public class Main { public void test(Map<String, String[]> map) { List<String> result = new ArrayList<>(); map.entrySet().stream().filter(entry -> entry.getKey().startsWith("x")).map(Map.Entry::getValue).forEach(arr -> { for (String str : arr) { result.add(str.trim() + arr.length); } }); } }