core/play/src/main/java/play/inject/BindingKey.java
public Binding<T> to(final Class<? extends T> implementation) {
    return underlying.to(implementation).asJava();
  }
public Binding<T> to(final Class<? extends T> implementation) {
    return underlying.to(implementation).asJava();
  }
Bind this binding key to the given implementation class.

<p>This class will be instantiated and injected by the injection framework.