Does Java do anything to prevent files from changing out from under it?

[Pete Soper]

Peter B. Kessler wrote:
> Does the Java platform do anything to prevent files from changing
> out from under it?  E.g., once one has opened a jar file for class
> loading, could a malicious (or oblivious) user write to the jar
> file and disturb the VM?  Or is that all relegated to "the operating
> system", file system permissions, etc.?
>
>             ... peter
No, yes, and yes for Sun Java SE on Solaris, Linux, and Windows. But 
somebody can just dd /dev/zero over the top of a raw disk device too if 
they "just have the permissions."

Deletion of a file is prevented by another process having it open on 
Windows, but that doesn't keep it from being overwritten and for rt.jar 
the program will explode when it tries to load the next class (depending 
on where the damage is).

-Pete