openCV dll problem : no opencv_java2413 in java.library.path

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I'm unable to get OpenCV to work within my Groovy/Grails web application, I've successfully included the jar and I can import all the libraries but when I try to run my app I get the following error :

no opencv_java2413 in java.library.path

I've already asked Grails and stackOverFlow but they recommanded me to open an issue here, to install OpenCv, I've first added gradle dependency :

compile files('libs/opencv-2413.jar')

(after adding the jar to libs folder for sure) and then added the required vm option as follow :

I'm using :
Windows 8.1
OpenCV 2.4.13
grails 3.1.5
Intellij Idea Version : 2016.1.2b

Thank you !