I found a fun and easy way to learn java a few months back.
About a year ago i played a game called runescape.I quit ages ago , but i found a website that lets you make your own server , and it's programmed in java.
The best thing about it is , you can invite other people to your server , and show off your coding skills.
The community is extremely nice , and you can find lots of tutorials.
http://moparscape.org <- web client
http://moparscape.org/moparscape.html <- desktop client (best)
http://moparscape.org/smf <- forums
Good luck.
P.S if it's not in the right place please don't blame me
i'm new.