The relationship between Japan and China has seen a lot of improvement and sure it's not been without any hiccups. But CPC and GOJ have always been cooperative since early on. Both sides trying to work together despite some nationalistic sentiments in each other's populace. Both want to look strong yet at the same time want to strengthen ties ; so it's diplomatic dance.
But overall majority of Japanese do want strong relations with China, and I know for a fact that Chinese feel the same with Japan. And I've a lot, a lot of Chinese friends in my university. I believe they are more representative of Chinese than some of the ultranationalists here in PDF, who are usually outliers.
BTW, if you know anything about Japanese and Chinese character it is this: we like to find middle ground, compromise. And that's why I believe Chinese and Japanese will cooperate.