// "Replace with toArray" "true" package com.google.common.collect; import java.util.*; class Sets { public static <E extends Comparable> TreeSet<E> newTreeSet() { return new TreeSet<E>(); } } public class Test { public String[] test(List<String> input) { Set<String> set = Sets.newTreeSet(); for(String s : inp<caret>ut) { if(s != null) { Collections.addAll(set, s, s+s); } } return set.toArray(new String[0]); } }