Re: [rvm-research] Building Jikes with a custom classpath location

Hi,

On 25.03.2017 04:50, Raoul Veroy wrote:
> I'm trying to build the latest version off Github and I wanted to use the system
> classpath. First of all, is that ok or is that a bad idea?

The short version: this isn't possible.

The long version: When you're writing that you want to use the system classpath, what I'm reading is that you'd like to use the libraries that your distribution provides to build Jikes RVM. In effect, this would be like having a Jikes RVM package from your distribution. This is currently not possible for several reasons:

Firstly, GNU Classpath isn't provided by any distribution and even if it were, our build process patches it in a few places. A switch to another classpath library (e.g. OpenJDK/IcedTea) is complicated because Jikes RVM is a metacircular VM.

Secondly, system Java libraries are probably compiled for Java 7 or 8 and Jikes RVM only supports Java 6. This is mostly a problem for JUnit and Hamcrest which are used to run unit tests on built Jikes RVM images. Adding Java 7 support to Jikes RVM would require a port to the OpenJDK class library to get support for all the required APIs.

> Secondly, if I wanted to do it that way, what do I need to change in the build files
> so that I can point the Jikes build to use the system classpath?

If you could somehow get around the problems mentioned above, you'd just have to look at the build system to determine how each library is expected to be used (e.g. as a jar file) and link and/or repackage those from the system classpath.

I'm not actually sure if this is a good approach, though. The components in the build system are rather annoying to use and it would make sense to switch to using a standardized system for components. I haven't evaluated this at all so I'm not sure if there's a system that would be a good fit (possibly with heavy customizations).


Kind regards,

Erik Brangs

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot