> 1.why java  wont support  multiple inheritance

Because multiple  inheritance is a inheritantly dangerous approach :)

If both Objects share the same methods which ones do you inherit? The
simple truth of the matter is that with the exception of C/++ ninja
activities there isn't much of a need for it over multiple interfaces.

> 2.write a java program  without using class

I don't know exactly what you are asking here ... If you are saying how
can you write  a java program that doesn't end up as a .class file, the
easy answer is that you can't. The more complex answer is there are
ways, but most of them are horrible and broken and the ones that are not
are often cheap and tacky.