You should not use them in your code either, as future releases will not support these anymore.
The correct phrase is not "will not", but rather "may not". No class or method has ever been removed from JSE, despite deprecations appearing as early as 1997 in Java 1.1
The Date class in particular has not been deprecated because it's faulty -it works just fine- but rather because it doesn't address all the issues one might expect a date/time library to address (like timezones). If those issues are not relevant to your code, then you should feel free to use them IMO. It does make for shorter code than the Calendar class.