I was using the jxls-2 library, but when I finish my work I've seen that I can't use it with my java version (java 6.22). Do you know if I can solve my problem without change my code? Or in the other side, if I decide to use a jxls older version, I'd have problems with my java version? That's my first question, by this reason, I'm so sorry if I don't ask correctly. Thank you!
If you cannot update to Java 7 or to Java 8 (strongly recommended) you have two options:
Use older Jxls 1.x version. Depending on your use case Jxls 1.x may be enough for you.
Checkout the source code for Jxls-2 and change the source/target java version in Maven compiler plugin from Java 7 to Java 6. Possibly you will need to do some minor code changes to compile it but it may also work out of the box.