just 512MB of RAM. Heck, there are phones with those specs that can't even get updated from Gingerbread to Ice Cream Sandwich (Hey Motorola, remember the Motorola DROID 3?) and here we are talking about Jelly Bean!
The update for the Sony Xperia J weighs in at 392MB which means that it will use some time to install. Make sure your battery is charged to at least 50% and that you have a strong Wi-Fi signal. And be prepared for the wonders of Android 4.1.2 like Project Butter, Google Now and the enhanced notifications page. It should feel like a brand new phone afterward.
Once you've run Android 4.1.2 on your Sony Xperia J for a while, let us know how smoothly it runs on your phone. Drop us a comment in the box below.
source: TheXperiaBlog via AndroidAuthority