Default [Q] Java client and GMail

Hi to all!
I'm a new owner of an ACER NeoTouch.
I was interested to install GMail app, but the phone does not have a Java client.
So I tried to install GC Java (including Opera Mini and Gmail).
I have two questions:
1. Why from the gmail app (even upgraded) i cannot write the password to login? (it allows me only to write the username).
2. what do I need opera mini for?

Thanks a lot to you all!

PS: anyone knows any good Medicine Application (IT)?

thanks again!