>>1094248>but presumably those are pronounced totally differently in Chinese?Yes, Chinese pronounciations are usually totally different, even though the hanzi (Chinese name for kanji) might be the same.
However, there are remnants of Chinese pronounciations in Japanese.
For example:
(I'll include both traditional and simplified hanzi)
太陽 / 太阳 Tàiyáng = 太陽 Taiyō = Sun
圖書館 / 图书馆 Túshū guǎn = 図書館 Toshokan = Library
準備好 / 准备好 Zhǔnbèi hǎo = 準備完了 Junbi kanryō = Ready
Another interesting note is that Japanese Kanji are based off the traditional Chinese hanzi. Although Traditional Chinese is still used in Taiwan, they use Simplified Chinese in mainland China. This means you get some slight differences in characters between Japanese and Chinese due to how the countries simplified some their characters differently, or due to the fact that only one country simplified the character.
Take a look at
https://en.wikipedia.org/wiki/Differences_between_Shinjitai_and_Simplified_charactersTo take my autism even further, there are even differences in the stroke orders between Chinese hanzi and Japanese kanji:
https://en.wikipedia.org/wiki/Stroke_order 
