core/src/com/google/inject/multibindings/MapBinder.java
public static <K, V> MapBinder<K, V> newMapBinder(
      Binder binder, Class<K> keyType, Class<V> valueType) {
    return newMapBinder(binder, TypeLiteral.get(keyType), TypeLiteral.get(valueType));
  }
public static <K, V> MapBinder<K, V> newMapBinder(
      Binder binder, Class<K> keyType, Class<V> valueType) {
    return newMapBinder(binder, TypeLiteral.get(keyType), TypeLiteral.get(valueType));
  }
Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
Map} that is itself bound with no binding annotation.