Translation:I hate rice.
I'm only guessing but I think じゃない is just a shorter and more informal version of ではありません which is the negative version of です.
So if です loosely translates to "it is" then じゃない can be treated as "it is not".
It takes the verb (as long as the verb is not in the past tense) and negates it.
So in this example:
好き - like
好きじゃない - do not like
That was a little offtopic I know.
I think its just that きらい is stronger language and shows an active dislike/hatred for something.
Whereas 好きじゃない is more impartial, not fussed.
You are 100% correct, じゃない is less formal than でわありません and everything else you said is true.
From the little bit of 日本語 I've learned, I've come to understand that the language is fairly particular about word choice. So while 好きじゃない and きらい translate to the same thing, きらい is contextually more negative
I just started the Japanese tree, having studied Japanese for a few years in the past. Why on earth does it mark this wrong: ご飯が嫌いです are you not supposed to use the kanji? it seems to randomly sometimes accept kanji and othertimes not, or expect some words to be spelled out with only hiragana, even when they are words that are always written with kanji in Japanese.