Yes, and no at the same time! Many Japanese and Chinese characters have the same meaning in both languages. However, Japanese uses some characters that do not exist in Chinese. For example, the Japanese verb 'to work' is 働く (はたらく). The character in that word (働) is Japanese-only. Some characters are used in both Chinese and Japanese, but have completely different meanings. The most famous example is probably 大丈夫 (だいじょうぶ) which means 'OK' or 'alright' in Japanese, but means 'gentleman' in Chinese. 湯 (ゆ) means 'hot water' in Japanese, but 'soup' in Chinese. The Japanese word for soup is 汁（しる), but it means 'juice' in Chinese. Confusing! Some characters are written differently in both languages. For example, the word for 'dragon' in Japanese is 竜 (りゅう), but the same character in Chinese is 龍 or 龙 depending on which kind of Chinese you are using (traditional in Hong Kong and Taiwan or simplified in the Mainland) I think somebody who can read Chinese would have an easier time learning Japanese than people with no experience, but they have to be careful not to get confused.

Justin had a great answer! I would compare the Chinese/Japanese thing to English/Dutch. There are some big similarities, but you won't automatically know Dutch without studying.