I'm in the process of learning Japanese... I learned kana (the hiragana and katakana alphabet) so far and now I need an on-screen keyboard for kana. I searched the package manager in ubuntu and found plenty of kana to kanji converters but not any on screen keyboards (well only english ones).

Where can I get a hold of one? I am prepared to make my own in java but just wanted to check to make sure it does not already exist as it will take a lot of work

Thanks in advance