I am travelling with Jetstar from manila to tokyo.. I have stopover at Osaka for 8 hours, am i allowed to go out the airport?
it depends on your nationality. If you're from one of these nations (including Australia, NZ and USA) http://www.jnto.go.jp/eng/arrange/essential/visa.html you can be issued with a visitor's visa on arrival. A stamp in your passport as you go through immigration (which you'll have to do anyway).
Why not check out our japan travel safety guide and visitor tips for Japan:
Phil at the safety hub about 6 years ago