// "Replace with forEach" "INFORMATION" import java.util.*; class A { public static void main(String[] args) { List<String> names = Arrays.asList("Bob", "Alice", "Bob", "Carol"); Set<String> uniqNames = new HashSet<>(names.size()); names.forEach(name -> uniqNames.add(makeNameUnique(name, uniqNames))); uniqNames.forEach(System.out::println); } private static String makeNameUnique(final String name, final Set<String> uniqNames) { if (uniqNames.contains(name)) { return name + "1"; } return name; } }