>>> Again, the ISP allows I run Java in his server because Java is "safe".
>
> Huh ? Java program can't send spam ? Or open socket ?

No, unless you provide an appropriate permission. Java is designed to
run in a sandbox mode. When you turn the security manager on, you might
not be able to even load particular classes, not only read stuff from
the disk or connect to a socket (not saying about opening a socket). And
it is possible to give disk access permissions to classes loaded from
one library and not to the classes loaded from another one.

So, Java _is_ safe (unless somebody finds some exploit, but that's
something that can happen to any code).

Roman