import com.google.common.base.Function; import com.google.common.collect.FluentIterable; import java.util.ArrayList; import java.util.List; class A { void c() { ArrayList<String> strings = new ArrayList<String>(); FluentIterable<String> i<caret>t = FluentIterable.from(strings); int i = it.transformAndConcat(getFunction()).size(); } Function<String, List<String>> getFunction() { return null; } }