Porting Hotspot to other platforms / OS'es

Michael Neuweiler michael at neuweiler.biz
Wed May 21 23:43:22 PDT 2008

Hi Andrew,

Thanks a lot for your fast response. I do share your opinion that 
building/bootstrapping at least the hotspot must _not_ rely on any other 
java technology but solely on the standard GNU toolchain (or similar). 
If the build of hotspot with gcc/gcj is possible, I wouldn't mind 
copying jar's over from an existing installation. That'd be ok - but no 
libraries or other platform/OS dependant binary.

In the meantime I discovered the porters-dev mailinglist where I was 
able to find dome interesting information and one possible solution 
(although it requires some special tweaks with a customized linux shell, 
ssh and nfs to the target environment) : 

I will also check with the developers of Haiku 
and the porters to MIPS 
to find out more.

I'll keep you informed on my progress and once I'm "blissed" with 
success I'll write a guide which could be added to the FAQ section.


Andrew John Hughes wrote:
> On 21/05/2008, Michael Neuweiler <michael at neuweiler.biz> wrote:
>>  Hi,
>>  I wanted to start porting OpenJDK to Syllable on Intel32 but got stuck with
>> the chicken and egg problem of hotspot: "you need a running JDK to build a
>> new one".
>>  What are your recommendations to start a port? Is cross-compiling the only
>> solution or are there other ways?
>>  I think I saw once that an XSLT is started with an already installed
>> JRE/JDK during the build process on my Linux machine. Is this the only
>> reason why a JRE has to be installed?
>>  Any help would be greatly appreciated!
>>  Regards,
>>   Michael Neuweiler
> (Adding distro-pkg-dev too)
> My understanding, both from building OpenJDK quite a number of times
> and from my own general thoughts on the issues of building a Java
> environment, is that bootstrapping the JDK through its standard build
> process is more than just handling XSLT.
> The first thing you're likely to run across is that there are no
> current Java compilers (as far as I know) that are not written in Java
> -- the main two are ecj from Eclipse and javac itself.  The first
> thing the OpenJDK build process does is build javac and the other
> language tools.  The current build not only depends on an existing
> javac to do this,  but a full-scale JDK to run ant.  My personal
> feelings are that it would have been better to stick with make for the
> langtools, but oh well...
> If my memory serves correctly, this is followed by JAXWS and JAXP,
> both of which require Java.  Thus, a sensible course of action might
> be to approach building HotSpot alone first.  Assuming this is
> possible (I have my doubts about it also including Java code), you
> could then use this to run an existing JAR file containing the tools
> to build.
> The reason I've CCed distro-pkg-dev on this is that a lot of work on
> bootstrapping on unsupported architectures (mainly the CPU rather than
> the OS) has been done under the auspices of the IcedTea
> (http://icedtea.classpath.org/) project.  Here, we've found gcj to be
> useful in breaking this bootstrapping cycle -- do you know if GCC
> (which includes gcj) is available for the platform you are working on?
> This might be the simplest course of action.
> Looking forward to hearing how this works out for you,
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