Re: GNU Classpath and JVMs

[Andrew Haley]

theUser BL writes:
 > 
 > What me everytime wonder is, that GNU Classpath have not its own VM.
 > 
 > To show the situation so, like I see it:
 > Suns Java comes as a complete package, which includes the Classes _and_ the 
 > JVM.
 > Mono comes as a complete package, which includes the .net-classes and the 
 > mono-runtime.
 > 
 > Only with GNU Classpath it looks a little bit different.
 > 
 > At first the developer changed the GNU Classpath code on any JVM, so that is 
 > no longer compatible to the old one.
 > So, when a new GNU Classpath version is released, there existing at first, 
 > no JVMs on which it can run.
 > 
 > After the release, the first JVMs are using the new Classpath version in its 
 > CVS. And later some using the new one. And some are being on older one 
 > (GCC-20050909 used still 0.17; SableVM used still 0.16 in CVS)
 > 
 > >From the new versions, which use 0.17 or 0.18, I can either not compile it 
 > or it (like JamVM), or it have problems with AWT and Swing (IKVM).
 > And a CVS-version of Kaffe I have not tried. But Kaffe 1.1.5 don't run Swing 
 > programs on my computer.
 > 
 > So I asked myself, what JVM does the GNU Classpath developer use?
 > They can not use a JVM, which still have a old version of GNU Classpath 
 > (like SableVM or Gcj).

gcj doesn't have an old version of Classpath; it's been changed so
that it comes with a recent tested version, and you can drop Classpath
CVS in if you wish.

 > And I don't understand, why GNU Classpath comes not with its own JVM.

You're missing the whole idea of Classpath, which is to provide a set
of class libraries for free VMs.  In this regard it is no different
from glibc, which is a C library, not a C compiler.

 > Other JVMs can then always later bringing GNU Classpath to its own JVM.
 > But at first it need a JVM as basis.
 > 
 > And it is not so, that GNU Classpath includes only the platformindependent 
 > parts.
 > The native libs like gtkpeers.so are existing, too. Why not then additionaly 
 > having the own JVM, which is then the standard JVM for GNU Classpath?

Keeping a clean separation between VM and library is a good idea.  The
problem that we are all trying to solve is to make sure that Classpath
runs "out of the box" on the free VMs.  We're getting there.

Andrew.