Is Japan a great power?
Japan is a great power. The reason is that as a nation, Japan is able to have global scale influence. It features diplomatic, economic and military influence, hence has status like other states Italy, China and USA, which have great power.
Yes. It's one of the worlds great powers.
no, only China and US are super-powers.
actually I don't even think they have an army anymore.
Power, in the sense that they are an economic power, a political power, a military power (though limited) and a friend of the USA, thus powerful through their alliances.