how to make jni.h be found?

Question

In Ubuntu 12.04, I have jdk7 from sun/oracle installed. When locate jni.h, it prints multiple locations

/usr/lib/jvm/java-6-openjdk-amd64/inclu         


        

Answer 1

You have to tell your compiler where is the include directory. Something like this:

gcc -I/usr/lib/jvm/jdk1.7.0_07/include

But it depends on your makefile.

Answer 2

Setting JAVA_INCLUDE_DIR to where jni.h is located should solve your problem (setting CPPFLAGS did not work for me)

Assuming it is /usr/lib64/java/include;

export JAVA_INCLUDE_DIR=/usr/lib64/java/include

Answer 3

Above answers give you a hardcoded path solution. This is bad on so many levels (java version change, OS change, etc).

Cleaner solution is to add:

JAVA_HOME = $(shell dirname $$(readlink -f $$(which java))|sed 's^jre/bin^^')

near the top of your makefile, then add:

-I$(JAVA_HOME)/include

To your include flags.

I am posting this because I ran into the same problem and spent too much time googling for wrong answers (I am building an app on multiple platforms so the build environment needs to be transportable).

Answer 4

Installing the OpenJDK Development Kit (JDK) should fix your problem.

sudo apt-get install openjdk-X-jdk

This should make you able to compile without problems.

Answer 5

It needs both jni.h and jni_md.h files, Try this

gcc -I/usr/lib/jvm/jdk1.7.0_07/include \
  -I/usr/lib/jvm/jdk1.7.0_07/include/linux filename.c

This will include both the broad JNI files and the ones necessary for linux

Answer 6

Use the following code:

make -I/usr/lib/jvm/jdk*/include

where jdk* is the directory name of your jdk installation (e.g. jdk1.7.0).

And there wouldn't be a system-wide solution since the directory name would be different with different builds of JDK downloaded and installed. If you desire an automated solution, please include all commands in a single script and run the said script in Terminal.