import com.google.common.base.Function; import com.google.common.collect.FluentIterable; import java.util.ArrayList; class A { void c() { ArrayList<String> strings = new ArrayList<String>(); FluentIterable<String> i<caret>t = FluentIterable.from(strings); int i = it.transformAndConcat(new Function<String, Iterable<String>>() { @Override public Iterable<String> apply(String o) { if ('a' > 2) { return getIterable(); } else if ('c' < 123) { ArrayList<String> strings1 = new ArrayList<>(); strings1.add(o); return strings1; } return null; } }).size(); } Iterable<String> getIterable() { return null; } }