Re: Java

[Philip Nienhuis]

marco atzeri-2 wrote
> John,
> just noted that there is no check on the config process to validate
> the presence of java.
> On my cygwin ambient, the Java compiler was not present and the build
> stopped almost at the end. Added it and re-testing.
> 
> It will be better also to add the possibility of disabling such
> new functionality, I am not confident about java on cygwin at all.

1. Seconded.

2. The way configure tries to find Java if no JAVA_HOME environment var has
been set is a work in progress, obviously. I acknowledge that finding the
Java stuff on the plethora of operating systems and distros is challenging
w/o a JAVA_HOME setting....

On my Mageia 2 development box there are several dummy and empty java*
directories under /usr/lib, configure simply takes the first which happens
to be java-1.5.0. At the end of configure I see that configure blindly
expects the include files to be there, but it hasn't checked if there really
is an include dir in /usr/lib/java-1.5.0.
The "real' Java JDK location is under /usr/lib/jvm/ where "java/" and
"java-1.7.0" are symlinks to the currently installed JDK
(./java-1.7.0-openjdk-1.7.0.6). (Can't help that, it's the way Mageia (and
Mandriva) has been set up)
The Java executables are symlinked in /usr/bin, not in one step but in a
number of steps, to the actual location in /usr/lib/jvm/java-<version>/bin/

IMO configure should rather test if it can really stat jni.h, the real Java
executables, and the jvm library (or jvm.cfg on Windows), and complain about
a missing JAVA_HOME setting if it doesn't find all of them. 
When Java was an OF package, installation woes usually boiled down to one or
more of these files not being found at compile time.

On Windows systems the Java executables are not in the default PATH; I think
on Windows a properly set JAVA_HOME environment variable is imperative but
even then the build can fail if javac.exe and jar.exe can't be found. In the
preinstall.m file in the latest OF package version these files were added to
the PATH in use by the Octave process.

3. I think it should be made clear somewhere (NEWS?) that a Java JDK is
needed to have Java support built; a JRE won't suffice.

Philip




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