Run icedtea-web using JamVM

Felipe Scarel fbscarel at
Mon Oct 6 13:00:15 UTC 2014

I succeeded in building IcedTea on the host system with pointers both
on and off-list. I appreciate all the help given so far.

I've built IcedTea using the default OpenJDK build, and from what I've
read there's no 'install' target; after 'make', the resulting build is
available on the '' directory. That's great, but the size
of that directory is a whopping 3.6GB, which is gigantic -- of course,
I assume there's a lot of stuff I won't need on my target system here,
such as documentation and build objects. Is there any documentation on
which directories/files are absolutely needed to run the web plugin
and should be copied from this '' directory? I assume
'bin/' and 'include/' would probably be needed, but I'm only guessing
at this point.

On a sidenote, I'm now building with the '--enable-jamvm' option to
check if the resulting size will be any smaller.


On Sat, Oct 4, 2014 at 4:40 AM, Robert Lougher <rob.lougher at> wrote:
> JamVM is a Java Virtual Machine.  It supports both the GNU Classpath
> library and the library from OpenJDK.  What you have on Buildroot is
> JamVM with GNU Classpath.  The IcedTea project, packages OpenJDK with
> additional VMs such as JamVM.  You could also build "vanilla" OpenJDK
> and then replace the JVM with JamVM.  Additional information is
> contained in JamVM's INSTALL and README files.
> Rob.
> On 4 October 2014 02:09, Felipe Scarel <fbscarel at> wrote:
>> This JamVM I was talking about is this project:
>> That said, I just checked Buildroot Makefile information for JamVM and
>> it uses GNU classpath on build, so that's out the window.
>> It's pretty clear I'll have to install openjdk-jre on the target
>> machine, then. I've successfully compiled the JDK on the host machine
>> in a test run, but for obvious size implications I'd like to "make
>> install" only the JRE on the target machine. I'll research how to do
>> that on OpenJDK docs and mailing lists, but if you have any pointers
>> on that (even though not directly related to IcedTea), I'd be
>> grateful.
>> Thanks for the help, Omair. Regards,
>> fbscarel
>> On Fri, Oct 3, 2014 at 5:31 PM, Omair Majid <omajid at> wrote:
>>> * Felipe Scarel <fbscarel at> [2014-10-03 14:48]:
>>>> The problem is I used OpenJDK-7 to build the image in my host environment, and
>>>> understandably IcedTea won't work on the resulting image, complaining 'java' is
>>>> not on the PATH. I have access to JamVM on Buildroot (as this package has
>>>> already been made available previously), so my question is: can I use
>>>> icedtea-web with JamVM (rather than OpenJDK-JRE)?
>>> Can you elaborate what this JamVM is? Is it the JavmVM virtual machine
>>> built so that it uses the OpenJDK class libraries?
>>> As far as I know, IcedTea-Web has almost no dependencies on the VM
>>> itself - it really just expects a working valid JVM. It doesn't really
>>> know anything specific about Hotspot. So, in a sense, a move from
>>> Hotspot VM to JamVM VM should be invisible.
>>> IcedTea-Web does care about the class libraries though. It is designed
>>> to work with OpenJDK's class libraries. It uses internal API that's not
>>> part of the Java SE specification. It wont work with GNU classpath, for
>>> example.
>>> Thanks,
>>> Omair
>>> --
>>> PGP Key: 66484681 (
>>> Fingerprint = F072 555B 0A17 3957 4E95  0056 F286 F14F 6648 4681

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