The HashMap extends AbstractMap and implements Map. But according to the API spec,
the HashMap get method does not document that it throws exceptions although the Map interface does and
specifies two: NullPointerException and ClassCastExceptions, both of which extend RuntimeException.
Examining the API for RuntimeException documents:
"A method is not required to declare in its throws clause any subclasses of RuntimeException that might be thrown during the execution of the method but not caught."