error: can't find jni.h

doh... thought I was in help.... sorry

"jni.h" is a system header. If your gcc was compiled with java support, it should just find jni.h without you doing anything. In general, if you can compile with gcj, then gcc should probably be able to find jni.h without any hints.

So, have you ever compiled anything with gcj? If not, try to compile "hello world".

It sounds as though you know java, so I will assume you can write HelloWorld.java :-)   Here is the syntax for compiling it with gcj:

$ gcj -o HelloWorld --main=HelloWorld HelloWorld.java

The --main=xxx option just tells gcj that class xxx is the one to actually execute. In principal, there could be many classes with many mains, and gcj wouldn't know which one to treat as the "real" main.

Let me know what happens.

--McKenzie

Hi McKenzie,

Thank you for responding.

I can compile HelloWorld.java with gcj.

I tried to install the 2 older versions of support with no luck also, but the ./configure completed on those ones, but it still said no jni.h.  make did not work though, saying that there was no jni.h..

I am running Mandrake 10.0 Official, and had the same problem on Mandrake 10 Community when I tried to install this a couple months ago.

I also tried linking the gcj and the java sdk jni.h to /usr/include to see if maybe it just wasn't seeing it, but that did no good either.  Also I probably should have posted more info on the error.  Here is all the info shown about jni.h during ./configure:

creating libtool
checking jni.h usability... no
checking jni.h presence... no
checking for jni.h... no
configure: error: Can't find jni.h

thanks again,
Jason Woodward

The fact that configure completed on the previous versions of the libswt support library is not significant. Those versions had a bug where they proceeded to completion even when jni.h could not be found.

I still believe that there is something wrong with your gcc installation that it doesn't find jni.h. The system should know where to find system headers!

But, if the jni.h that you have is good (i.e., it matches your gcc and gcj versions), you can just add an include flag for it to the CFLAGS environment variable prior to running ./configure.

Based on your first post, that would look like this:

$ export CFLAGS=-I/usr/include/libgcj-3.3.2\ $CFLAGS
$ ./configure

Try this and let me know how it goes.

I might as well mention that non-bash users may need to use a different syntax to set environment variables.

Using export CFLAGS=-I/usr/include/libgcj-3.3.2\ $CFLAGS worked.  I was able to install both the support and then the libswt.  I can't run ./Hello though.  I get an error saying:

./Hello: error while loading shared libraries: libswt-gtk2.so: cannot open shared object file: No such file or directory

locate libswt-gtk2.so shows: /usr/local/lib/libswt-gtk2.so

I found the answer in another post on this forum:

$ export LD_LIBRARY_PATH=/usr/local/lib:${LD_LIBRARY_PATH}
$ ./Hello

Thanks again for your help,
Jason