You can use
Map<String, List<String>> myMap = new HashMap<>();
Map<String, List<String>> myMap = new HashMap<String, List<String>>();
However, you can't use
List<String> list = new ArrayList<>(); list.add("A"); // The following statement should fail since addAll expects // Collection<? extends String> list.addAll(new ArrayList<>());
because it can't compile. Note that the diamond often works in method calls; however, it is suggested that you use the diamond primarily for variable declarations.