My new *Samsung Galaxy Advance S* is running with android Gingerbread. I am thinking to upgrade it to Jelly Bean. I am very new to Android devices.

I have following basic questions

 1. Are there any known advantages and disadvantages in upgrading my device to JellyBean?
 2. If I upgrade to Jelly Bean do my all apps remain works?
 3. Upgrading OS, does it void my warranty?
 4. Is there any official instruction to upgrade my phone to Jelly Bean?

Thanks in advance