How do the Japanesse feel about cheap laboured, Chinesse goods?

In terms of cheap labour and inhuman practices, I don't think anyone in Asia gives too much thought. Everyone likes a bargain and most people in China are actually happy about the situation (that includes many factory workers, who earn very little by western/Japanese standards but a lot more than they would otherwise earn on their family farms).

In terms of product quality, I think everyone - Chinese included - agrees that Made in China products are, generally speaking, of inferior quality compared to Japanese-made items and occasionally even dangerous.

I don't think Chinese labour practices affect the Japan-China relationship at all. As someone mentioned above, Made in China products sell well because they're cheap. Japanese companies are happy, Chinese manufacturers are happy.

However, safety scares such as the melamine-in-milk scandal and poisonous dumplings do affect the relationship. The Chinese government is (rightly) blamed for not doing enough about product safety, and many Japanese people thus have a (often exaggerated and stereotyped) image of China as a place where evildoers churn out harmful products.

In my experience, Japanese tend to have similar feelings to Americans about it. The most common feeling is that Chinese-made goods are of low quality, especially compared to Japanese-made goods. This especially relates to food products; there have been some food poisoning scares in recent years and many Japanese try to avoid buying Chinese-made food (but it's hard or impossible to avoid completely).
The labour conditions are a lesser concern.
There's also a feeling, just like in the US, that cheap Chinese goods are going to drive domestic industry out of business in the end.
But just like in the US, despite these feelings, people keep buying the stuff because in the end, the cheap price wins them over.

how much can china's products be a threat to japan's economy? one point to make is that even though a product is labeled "made in china" that does not mean all the parts of the product are produced in china. most advanced parts of it are generally from small or middle sized factories in japan whichi are highly specialized in making them. even bailing out big3 helps japan's economy a bit since they buy components from japanese firms. likewise your xbox contains japanese ICs, your samsung flat panel have many parts from japan and many other cases.

just as americans, canadians, australians, europeans whites who historically have been the exploiting race feel.

Hmm... I'm pretty sure us East Asians, don't really give a crap when it comes to China's cheap labor thing. Generally we're too busy thinking about the next test or finding a job in this economy then inhumane practices. Also, our ethic ties do not make us closer at all. Most of the Chinese and Korean still hasn't forgiven the Japanese for their war crimes since they didn't really repent with the same fervor as the Germans did and all the "official" apologies are contradicted all the time. The Chinese and most East Asians dislike the Japanese in general and the Japanese probably aren't really sympathetic towards people who hate them. To sum it up, people in the US care far more about China's inhumane practices than Japan. Since the practices aren't even concerned it does not affect Japan and China's relationship.
and.... Just throwing this out there Samsung's not the one who receives part from Japan for their LCD flat panels, rather it's the other way around.

Creates jobs in China and high profit returns for Japan. Almost everyone is happy.

With the world economic on a down turn and Japan in recession today, I would say cheap labour and goods would be ideal for people who want to cut costs.