Error #04

[ioiops]

Hello,

When I try to import the r extension, I get the following error:

Error in R-Extension: Error in runOnce (Error #4): java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')

I have:

Netlogo 6.4.0
R 4.4.2
Windows 11

Thank you!

[eafulton]

I have the same issue on macOS Sequoia (version 15). From what I can find by google it is likely due to something like a java vs jdk incompatability.

See page https://forums.oracle.com/ords/apexds/post/classcastexception-with-appclassloader-and-urlclassloader-i-3230
where there is a comment " The system/application class loader was implemented as URLClassLoader in Java 8. Classloading changed in JDK 9."
Checking my machine I'm running JDK 21

[brandesNW]

Hi,
Thanks for reporting this. We will address the issue. NetLogo bundles its own JDK which is currently Java 17.

• Aaron

[D2Joy]

same issue here..netlogo 6.3+ require jdk 11+, but r extension require jdk 8. They will never work with each other.
plus, when I use netlog 6.2.1 with jdk 8, the model involving r extension open up crash, with no log. No idea what is happening.