guava/src/com/google/common/collect/MutableClassToInstanceMap.java
public static <B> MutableClassToInstanceMap<B> create() {
    return new MutableClassToInstanceMap<B>(new HashMap<Class<? extends B>, B>());
  }
public static <B> MutableClassToInstanceMap<B> create() {
    return new MutableClassToInstanceMap<B>(new HashMap<Class<? extends B>, B>());
  }
Returns a new {@code MutableClassToInstanceMap} instance backed by a {@link HashMap} using the
default initial capacity and load factor.