FastNumber extends Number { public static FastNumber orNull(@NonNull Number number) { if(number == null) { return null; } else { return new FastNumber(number); } } private  FastNumber(@NonNull Number number); static FastNumber orNull(@NonNull Number number); @Override int intValue(); @Override long longValue(); @Override float floatValue(); @Override double doubleValue(); @Override boolean equals(@Nullable Object o); @Override int hashCode(); @NonNull @Override String toString();  }
@Test public void orNull_returnsNull_ifNullNumber() { assertNull(FastNumber.orNull(null)); }