JNInotes.txt

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Gotchas:

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+export -p shows all PATH variables
+to export permanently use export command inside of:
	~/.profile
	~/.bash_profile
	/etc/profile

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Use JDK/JVM matching arch level of machine 
(i.e. 32 or 64-bit must match gcc compilations if
using JNI)

Notes on JDK installation:

download jdk...tar.gz
cd to usr/local
sudo -s >>> to signn on
tar zxvf /home/dan/Downloads/jdk...
exit >> exit root user

add to ~/.profile
export JAVA_HOME=/usr/local/jdk...
export PATH=$PATH:$JAVA_HOME/bin


actually im using ~/.bashrc
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Add C header library for JNI files for gcc through
environment variable examples:

C_INCLUDE_PATH=/usr/local/jdk1.8.0_31/include
export C_INCLUDE_PATH

C_INCLUDE_PATH=/usr/local/jdk1.8.0_31/include/linux
export C_INCLUDE_PATH

Use this one 31 for 64 bit or change 31 below to 25 for 32 bit:
C_INCLUDE_PATH=$C_INCLUDE_PATH:/usr/local/jdk1.8.0_31/include:/usr/local/jdk1.8.0_31/include/linux

Or this one specifing variable differently:
C_INCLUDE_PATH=${C_INCLUDE_PATH}:/usr/local/jdk1.8.0_31/include:/usr/local/jdk1.8.0_31/include/linux

This one includes current directory which is not needed:
C_INCLUDE_PATH=/usr/local/jdk1.8.0_31/include:/usr/local/jdk1.8.0_31/include/linux:./

//add path variable
export C_INCLUDE_PATH

//display
echo $C_INCLUDE_PATH

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-> make java class 

->dont forget C_INCLUDE_PATH
-> generate c header for dll / shared object
-> generate c source using header
-> created dll / shared object
-> invoke java code

javac HelloWorld.java ---> generate HelloWorld.java
javah -jni HelloWorld ---> generate HelloWorld.h

-> shared object 

LD_LIBRARY_PATH=./  ---> set current directory 
export LD_LIBRARY_PATH
java HelloWorld