People tend to think kanji = Japanese, but that's not nearly the case. It's one of the scripts used to represent it graphically, but it isn't the language. So, you can't say 私好食ケーキ or something nonsensical like that, because that doesn't represent anything but an English-bastardized attempt at Japanese based only on what each character means. If you're wondering, the Japanese version would be (私は)ケーキを食べるのが好きだ.