import java.util.ArrayList; import java.util.Collection; public class ExtractVariableSample { interface I { void foo(String s); } public static void main(String[] args) { Collection<String> strings = new ArrayList<>(); I i = (s) -> { int j = s.hashCode(); System.out.println(j); }; for (String s : strings) { System.out.println(s.hashCode()); } } }