OpenCV error in Processing 4.0b2

Processing Libraries
#1

I’m preparing a workshop using Processing 4.02b, but OpenCV library seems to have an issue with permissions.

WARNING: Illegal reflective access by gab.opencv.OpenCV (file:/Users/Name/Documents/Processing/libraries/opencv_processing/library/opencv_processing.jar) to field java.lang.ClassLoader.sys_paths
WARNING: Please consider reporting this to the maintainers of gab.opencv.OpenCV
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
NullPointerException

Any suggestion to run OpenCV again?

#2

This a java feature since java 11, but is normally (up to jdk11 at least) only a warning that you can ignore. Ideally you want the OpenCV library updated to module version that explicitly permits reflective access.

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#3

hence, what would be the solution, in particular to that NullPointerException?

#4

The problem is not the warnings themselves. The warnings are telling you the library is doing something it shouldn’t be. In this case, setting a private field to null in such a way that worked in JDK 8 and throws an exception in JDK 11 - the internal behaviour of ClassLoader has changed quite a bit.

Also see java - Processing 4 error: WARNING: Illegal reflective access by gab.opencv.OpenCV - Stack Overflow

#5

hi Neilcsmith
Thanks for the link. The solution for Processing 4 is here in this link

#6

Thanks for OpenCV for Processing 4.

However, I still got the error “A library used by this sketch relies on native code that is not available. UnsatisfiedLinkError: no opencv_java400 in java.library.path: :/Applications/Processing.app/Contents/Java/core/library/macos-x86_64:…”

Do you maybe know what can cause this?

#7

I am receiving the same exact error despite that fix. Have you been able to resolve this issue yourself?

#8

Yes, I solved it by copying the file “libopencv_java400.dylib” to /Applications/Processing.app/Contents/Java/core/library
Of course, with updated library from above. Let me know if it fixed your case.

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