"java -jar MCreator.jar" kicks an error on OS X High Sierra

Works as designed
Not applicable
Issue description


When I try variations of double clicking the jar, or running variations of "java MCreator.jar", I get the following error back:

vagner@Jasons-New-Air:~/Downloads/MCreator$ java -jar mcreator.jar 
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by co.pylo.mcreator.f.e (file:/Users/vagner/Downloads/MCreator/mcreator.jar) to method java.net.URLClassLoader.addURL(java.net.URL)
WARNING: Please consider reporting this to the maintainers of co.pylo.mcreator.f.e
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
[Tue May 15 20:47:58 PDT 2018] Exception in thread "main" [Tue May 15 20:47:58 PDT 2018] java.lang.IllegalArgumentException: object is not an instance of declaring class
[Tue May 15 20:47:58 PDT 2018] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[Tue May 15 20:47:58 PDT 2018] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[Tue May 15 20:47:58 PDT 2018] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[Tue May 15 20:47:58 PDT 2018] 	at java.base/java.lang.reflect.Method.invoke(Method.java:564)
[Tue May 15 20:47:58 PDT 2018] 	at co.pylo.mcreator.f.e.a(Unknown Source)
[Tue May 15 20:47:58 PDT 2018] 	at co.pylo.mcreator.f.e.a(Unknown Source)
[Tue May 15 20:47:58 PDT 2018] 	at co.pylo.mcreator.Launcher.main(Unknown Source)
vagner@Jasons-New-Air:~/Downloads/MCreator$ java -version
java version "10.0.1" 2018-04-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.1+10)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.1+10, mixed mode)

I've searched the wikis and the forums and haven't seen any advice that would help.

Any suggestion would be appreciated!


Issue comments

MCreator only works with Java 8. You are using Java 10. Please make Java 8 as the default Java version on your computer.

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