From: Erik B. <eri...@gm...> - 2012-03-24 16:57:25
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Hi, I'm cc'ing Xi Yang because he's been working on support for OpenJDK. On 24.03.2012 16:56, Thomas Preud'homme wrote: > Le samedi 24 mars 2012 16:25:12, Erik Brangs a écrit : >> Hi, >> >> >> What's the current status on the version update for the dependencies? >> >> If you've got any useful patches for that or something else, please >> don't hestitate to contact us. > > Sorry, I should have sent a message earlier. I'm sorry but unfortunetely no, I > didn't do any progress since quite a long time because I entered the end of my > PhD and my spare time has shrunk a lot. Ok. If you decide to continue work on packaging Jikes RVM, you can contact us (well, at least me ;-)) anytime if you have questions. > > However I will take advantage of this email to ask you a question about > JikesRVM internal, more precisely about the use of GNU classpath. > > Is the GNU classpath needed for building Jikes RVM, running java programs with > Jikes RVM or both? I think this question has also been discussed based on your last mail, the thread in the list archives is at http://sourceforge.net/mailarchive/message.php?msg_id=27974193 , therefore I'll answer it only briefly. GNU Classpath is currently needed both for building and running java programs: 1) We currently patch the class libraries, so we need them for building. It might be possible to change the build process to use prebuilt versions. Ian Rogers has done so for Apache Harmony on Windows for MRP. 2) We can't run Java programs without a class library because the class library provides the classes from the Java API. > Why openjdk classpath can't be used? (this one is more out of curiosity, I > want to understand the difficulty behind it). Well, theorethically it can be used. It's just a question of someone doing the work on integrating it with Jikes RVM. It's not nearly "plug-and-play" ;-). Xi Yang ( http://people.cecs.anu.edu.au/user/3937 ) has been working on support for OpenJDK. His work is available at https://code.google.com/p/openjdk4jikesrvm/ , branch openjdk. If you've got any specific questions, he can likely answer them. AFAIK he's using prebuilt versions of OpenJDK. > > I asked about the possibility of reintroducing GNU classpath in Debian and > here is the answer I got: > > < drazzib> BTW, I don't think it's a good idea to reintroduce a separate > classpath package > < drazzib> we already had issues between arch having GCJ as default and arch > having openjdk as default > < drazzib> having multiple VM (hotspot, jamvm, cacao, zero/shark) is great > < drazzib> but classlib... hum, no so so nice In the long term, we will probably switch to OpenJDK as standard class library. We just don't know when that's going to happen. I also don't know if it's feasible to use a prebuilt OpenJDK from Debian, you'd have to ask Xi Yang about that. > The next question is what version of java is Jikes RVM compatible with? I > remember I read some while ago it was compatible with java5. Is it compatible > with older or newer versions? We're definitively not compatible with Java 7 or later because we don't have support for the new invokedynamic bytecode that was added in Java 7. The rest depends on what you mean by "compatible". The API that we offer to java programs is the same that the class library we're using (e.g. GNU Classpath) offers. A Jikes RVM built with GNU Classpath currently has 1.6.0 as java.version property though I'm not sure if the version of GNU Classpath we're using is fully compatible with Java 6. Strictly speaking, the Jikes RVM probably isn't compatible with any version of the Java Virtual Machine specification though that is mostly unintentional. We're most likely less compatible than most (if not all) of the other free JVMs. For example, we don't have a bytecode verifier. Kind regards, Erik Brangs |