Re: Java support in MXE build

[Philip Nienhuis]

(maintainers list cc'd)

Anirudha Bose wrote:
> On Wed, May 15, 2013 at 5:55 PM, PhilipNienhuis <address@hidden
> <mailto:address@hidden>> wrote:
>
>     Until now the MXE building process fails to include Java support.
>     Looking at
>     the log from a freshly checked out MXE build I see:
>
>     configure: WARNING: JAVA_HOME environment variable not initialized.
>     configure: WARNING: Auto-detection will proceed but is unreliable.
>     checking for java... /usr/bin/java
>     /home/philip/devel/octdev/mxe-octave/tmp-octave/octave-3.7.5/configure:
>     line
>     66352: pwd: -W: invalid option
>     pwd: usage: pwd [-LP]
>     checking for javac... /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.19/bin/javac
>     checking for jar... /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.19/bin/jar
>     checking for Java version... 1.7.0_19
>     checking for jvm.dll... not found
>     configure: WARNING: Library jvm.dll not found.  Octave will not be
>     able to
>     call Java methods.
>
>     So the configure script defaults to the Linux Java system on the box
>     where
>     MXE is run.
>
>     I then tried to configure with the Windows Java system, installed on
>     another
>     (windows 7) partition, by adding a few configure options in
>     ./mxe-octave/src/octave.mk <http://octave.mk>   (symlink /mnt/jhm
>     points to /mnt/win7/Program
>     Files/Java/jdk1.7.0_21):
>
>     :
>              JAVA_HOME="/mnt/jhm" \
>              --with-java-homedir="/mnt/jhm" \
>              --with-java-libdir="/mnt/jhm/jre/bin/server" \
>
>     --with-java-includedir="/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.19/include"
>     \
>     :
>
>     I had to make the symlink as configure hickups on spaces in path
>     names. This
>     trick seemed to work, but then I got other errors:
>
>     :
>     - checking for java... /usr/bin/java
>     /home/philip/devel/octdev/mxe-octave/tmp-octave/octave-3.7.5/configure:
>     line
>     66352: pwd: -W: invalid option
>     pwd: usage: pwd [-LP]
>     checking for javac... /usr/bin/javac
>     checking for jar... /usr/bin/jar
>     checking for Java version... 1.7.0_19
>     checking for jvm.dll... /mnt/jhm/jre/bin/server
>     checking for include file <jni.h>... not found
>     configure: WARNING: Include file <jni.h> not found.  Octave will not
>     be able
>     to call Java methods.
>     :
>
>     Setting JAVA_HOME to the Java installation on the Windows partition
>     doesn't
>     help in any way.
>
>     So it seems the configure script consistently picks up the native
>     (Linux)
>     Java version and seems to largely ignore the --with-java-* configure
>     options. It does find the jvm.dll (that configure option works) but not
>     jni.h while the latter does live in the "java-includedir" indicated
>     in the
>     configure options.
>
>     Obvious question: how can we proceed with getting Java support
>     included in
>     MXE builds?
>
>     Philip
>
>
> Hey Philip. Can you send me your copy of src/octave.mk
> <http://octave.mk>. I am also working on getting Java enabled in MXE but
> presently stuck with "Library jvm.dll not found". Is it possible to get
> Java enabled in cross builds? The Linux system from which we are
> compiling surely doesn't contain any DLL files, and the only obvious
> option is to use the Java installation of Windows.

(Sorry short answer, I have other plans this weekend)

Read my last posting in that thread.

I had configure options pointing to the Windows-installed Java JDK.
Watch out for 64-bit vs 32-bit Java (client vs server subdir in the JDK).

I simply added the relevant configure options to the octave.mk file (+ 
symlinked a few things), and then the configure script picked up the 
proper Java stuff (i.e. the JDK on the Windows side on that machine).

However I soon ran into more obscure problems that I reported earlier in 
the maintainers ML:

https://mailman.cae.wisc.edu/pipermail/octave-maintainers/2013-May/033675.html

(i.e., the errors starting with dldfcn/.libs/__dsearchn__.o: In function 
`~octave_base_value':
/home/philip/devel/octdev/mxe-octave/tmp-octave/octave-3.7.5/libinterp/octave-value/ov-base.h:211: 
undefined reference to `vtable for octave_base_value'
etc
etc)

I suppose the symlink / configure option trick (for cross-compiling) 
itself worked OK, as in later native MXE-MinGW build I got exactly the 
same error messages. Same for a development tip building with the 
MXE-built dependencies. I the post I linked to above I also reported the 
same issue that I got with MinGW builds earlier on. Perhaps something is 
wrong with the Java configure options for MinGW.

Anyway, that's how far I got.

Philip