Building OpenJDK 7 on Windows XP

[Rob Ross]

Hi there everyone.

This will officially be my first email to the OpenJDK project.

I got to attend a couple of sessions/BOFs at JavaOne2008 about  
OpenJDK and my interest was piqued. I've been playing with the build  
for the last week. (A more accurate description would be, "yanking my  
hair out and cursing my computer quite often", but I supposed it's  
part of the learning curve.)

I was finally able to get "make sanity" to pass this evening, and I  
felt quite pleased with myself. However, I have no expectations that  
this will actually build now - but I still consider this a milestone  
victory.

Some of the difficulties I encountered were

1. Just assembling the prerequisite software
The jdk7/README-builds.html actually does a fairly good job of  
listing everything needed. But I'm not a Windows developer, so  
finding a copy of VS .Net 2003 was a little challenging. Luckily that  
install process was pretty simple. The build generates a warning if  
Ant and FindBugs aren't locatable; those were easy to install but  
perhaps you should add these programs to the list of requirements in  
the README. Cygwin was also pretty easy to install after spending a  
little time reading up on it. Finding an earlier version of make  
(gmake) was a little hard, but I see now there are links in the  
mailing list archive so that would be useful to add a link to the  
README as well.  Some of the Categories/package names you gave for  
the particular cygwin utilities needed may be out of date. Zip and  
Unzip are found in the Archive category, not Utils as described in  
the README. "Free" is listed as being in Utils but it's actually part  
of the "procps" package, under the System category. And there isn't  
an "awk" implementation, but there is a gawk. Freetype was the bane  
of my existence for 3 days. I never could get the "stock" build  
scripts to work with the version you stated was needed (2.3.0), and  
what was available to be downloaded (2.3.5). I could not figure out  
how to build it from source either via DOS/windows or cygwin. So I  
ended up downloading the binary setup executable, which contained  
freetype.lib, freetype6.dll, and zlib1.dll, and a freetype.dll.a that  
was a red herring. I modified the Makefile for the freetypecheck tool  
to change the name of the expected dll from "freetype.dll" to  
"freetype6.dll", and added its dependent "zlib1.dll" to the copy  
command. Not a very portable solution I know, but I just wanted to  
get this thing to work! How is everyone else getting this to compile?

2. Mercurial - well, it's new, and a little more complicated than CVS/ 
SVN, but I think I'll get the hang of it. I fcloned from the jdk7  
master forest, (using the forest extension) yesterday, so I have the  
latest code (baring any changes in the last day). It will be a while  
before I even have to worry about wanting to submit anything back  
upstream, so I should be more comfortable with how it all works by then.

3. Setting up the ALT_* environment variables
The hardest part, and mostly trial-and-error, was determining what  
variables needed to use the cygwin path syntax, and what needed to  
use the normal Windows path syntax, and what needed to be  
"shortcutted" by using the cygpath utility. This was mind numbingly  
frustrating!!!! I found an email from Tim Bell that included his  
sample script that was quite helpful in getting the right directories  
from the VS .Net 2003 install into the PATH, LIB, and INCLUDE  
variables, with the right syntax. As I was writing this email my  
initial "gmake all" build failed, due to javac not being able to find  
the binary plugins I had specified in ALT_BINARY_PLUGINS_PATH. It  
seems THAT one needs to be a java IO file path! So now there are  
THREE different path syntaxes in use in this script file :)


Anyway, I just wanted to share my experiences building the OpenJDK 7  
on Windows.

Ironically, I'm only doing this to get some practice on the existing  
build process. My ultimate goal is to port the OpenJDK 7 to Mac OS X,  
as a full native app. I'm doing some preliminary analysis on the  
existing code base to determine all calls to native methods, to get   
a sense of the scope. For example, there are currently about 421  
native method calls in the jdk/src/share classes. The Windows  
implementation classes make 210 native calls, and the Solaris  
implementation makes 299. But the first task would be to integrate  
Mac OS build targets into the OpenJDK 7 project, so it can be built  
on that platform. (Of course, it won't actually run without any  
native implementation - that's step #2.) But I'll be making a more  
formal presentation/declaration/request for sponsorship/ at a later  
time.

Rob Ross