All of the basic characters have the same meaning in both Chinese and Japanese. Most of the compound words (those made up of two or more characters) are the same in Chinese and Japanese as well except for some.
Single characters were imported from China to Japan directly. However, after the Japanese mastered Hanzi, or Kanji, they started making their own compound words to fit their own culture as well as import Chinese compound words. Around late 1800's and early 1900's, China also imported a few compound words from Japan.
In conclusion, Chinese and Japanese Hanzi/Kanji are more similar than different. In that t-shirt, the only compound word I didn't know was the one for "girlfriend". In Chinese, girlfriend is nupengyou



, which literally means "female-friend".