I have a question about Apache Commons projects. We know there are many nice classes and methods are available in Apache Commons Projects. But it is related to particular Java edition, I think. If I start use Apache Commons projects now, when Java updates itself to 1.8, I have to make sure Apache Commons projects has the similar update before I update to Java version 1.8? Having some 3rdparty libs is a good thing but I always worry about the compatibility between them and the main programming language I am using.
In general Java is fully backwards compatible, so if you start using e.g. commons-io in JSE1.6 it's going to work in JSE1.8 as well. Working with Java since 1999 I've never seen any issues regarding backwards compatibility.
EDIT: As long as Oracle does not change its compatibility policy, you should not run into trouble. If you later run into trouble anyway, you still have the source to fix it on your own (but may have to give back to the community depending on the license).