I ask this question because I am a business major and I`m curious about Japan. I know they are really innovative and their economy is one of the top but China is going to overtake their reign in a while so should I learn mandarin instead? Everybody is learning mandarin now. I read online that eventhough Japan is wealthy its economy is shrinking because of the population decline . Does that mean its not worth it?

One of six people in the world is Chinese. Go to any store and see how many things say "Made in China". Bush has borrowed millions from China. They're going to rule the world one day...

Japan will still be a very powerful country in the future years, and china will follow eventually. I think you might as well learn both languages.

How about learning both languages? It is always a great assets to have multiple languages.

My general understanding about Japan is that if you are a woman (and not white), you might not be as sucessful as a white men doing business there. However, if you looking for a job in Hawaii now, knowing Japanese give you THE BEST advantages. A lots of Japanese visit Hawaii and knowing how to interact with them is a GREAT skill!

As for China, it is taking step to be more modernized. In fact, in their large cities, they are pretty up to date with lots of opportunities. People in China are taking up English as a second language. So, in the future, you probably don't need to speak Mandrine to communicate with them. Of course, it will be nice to know what they are talking to each other during a business transaction. However, there are hundreds of sub-languages you can't possiblity learn all.

"Everybody is learning mandarin [sic] now."
If you're going to major in business, you need to try and be an important, worthwhile asset to your company. While, yes, it is strongly speculated that China will be the next big thing and will probably come to be true, this doesn't mean Japan will be out of the market and will plummet into a third-world country. It will still be making innovations in all fields and companies will still want to deal with them.
While all those people who spent their college years learning Mandarin are battling for the same jobs, you can have a step up on them for you can aid your company in gaining profits from the Japanese. Besides, who's to say you can't learn Mandarin as well?