Re: java policy for debian, shared libraries...
On Mon, Sep 16, 2002 at 10:00:22PM +0200, Robert Olofsson wrote:
> Ola Lundqvist wrote:
>
> >>I currently develop jmp (http://www.khelekore.org/jmp/) a java profiler.
> >>Java profilers are written in C/C++ and compiled to shared libraries,
> >>libjmp.so for jmp. Many profilers today have a java front end, jmp does
> >>not (it uses a gtk front end).
> >>
> >>
> >What exactly is a java profiler? A java debugging utility?
> >
> >
> A java profiler is a library and/or program that show how much memory
> your java program allocates,
> where it allocates it. Whats java objects are currently on the heap. It
> also shows where your program
> spends time (how much time each method take).
>
> It is a sort of debugging utility, but not the normal one where you run
> your program to breakpoints...
>
> Screenshots of jmp can be found at:
> http://www.khelekore.org/jmp/screenshot.html
Thanks now I understand.
> >>jmp is C code only.
> >>jmp is compiled by gcc.
> >>jmp has no binary (only libjmp.so is installed).
> >>libjmp.so should probably go into /usr/lib/ or someplace like that.
> >>
> >>
> >According to this it has nothing to do with java.
> >
> Most other java profilers have a java front end, jmp does not. So some
> java debuggers and profilers
> will show up that in a way has nothing to do with java but are libraries
> that are run from inside the jvm.
> They also require some java headers from the jvm to compile.
Ok.
> >>jmp needs a jvm to run (java -Xrunjmp my.fine.Program). The jvm loads
> >>the library with dlopen.
> >>
> >>
> >But this of course makes it java-related. Does it work with any jvm or
> >just some specific? Actually I do not think this has to be covered by the
> >java policy.
> >
> Jmp works well with the jvms from sun(1.3.x, 1.4.x), blackdown (1.3.x,
> most probably 1.4.x) and ibm (1.3.x).
> I havent tried any other jvm. Java profilers are coded according to the
> jvmpi specification.
> http://java.sun.com/j2se/1.4.1/docs/guide/jvmpi/jvmpi.html
Try kaffe if you can. It is the only jvm "inside" debian. :)
> >>The java debugger also has a similar interface but I am not aware of any
> >>debugger that does not use any java classes.
> >>There probably exists more interfaces that use dynamic loading to do
> >>strange stuff with the jvm....
> >>
> >>Where to this fit in?
> >>
> >>
> >In the normal debian policy. We just have to make sure that the
> >java-policy excludes this possibility. I just checked and I do
> >not think it does.
> >
> ? should that not be: ... java-policy not excludes this....
Doh! Of course :)
> >Do you think something is needed in the policy?
> >
> Not sure, but I noted that there is no place for tools that extend the
> jvm with dynamic libraries...
> What about external jits? (Just In time Compilers)? probably same thing....
Probably. Maybe it should be mentioned.
Dynamic extensions
A dynamic library/program that extend the jvm or compiler without the
use of java classes are treated as a ordinary library/program and thus
treated as such (i.e. not covered in this policy).
What do you (all?) think?
Regards,
// Ola
> /robo
>
>
--
--------------------- Ola Lundqvist ---------------------------
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