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Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841795] Sun, 30 May 2021 07:54 Go to next message
Benjamin Govedarovic is currently offline Benjamin GovedarovicFriend
Messages: 3
Registered: May 2021
Junior Member
2021-05-30 09:51:25,042 WARN Unable to instantiate org.fusesource.jansi.WindowsAnsiOutputStream
2021-05-30 09:51:25,045 WARN Unable to instantiate org.fusesource.jansi.WindowsAnsiOutputStream
[09:51:25] [main/INFO] [GradleStart]: Extra: [username=<username>, password=<password>]
Exception in thread "main" 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')
at net.minecraftforge.gradle.GradleForgeHacks.searchCoremods(GradleForgeHacks.java:87)
at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:86)
at GradleStart.main(GradleStart.java:26)

I tried to setup eclipse for minecraft coding but I constantly get errors.
Re: Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841837 is a reply to message #1841795] Mon, 31 May 2021 21:14 Go to previous messageGo to next message
Denis Roy is currently offline Denis RoyFriend
Messages: 477
Registered: October 2004
Location: Ottawa, Ontario, Canada
Senior Member

I've tried this a few months ago, and had the same experience. The problem is that most sites don't update their instructions with the latest versions of Minecraft, so you have to use the exact version of each dependency.

Denis Roy
Eclipse Webmaster -- webmaster@eclipse.org
Re: Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841886 is a reply to message #1841837] Wed, 02 June 2021 09:44 Go to previous messageGo to next message
Benjamin Govedarovic is currently offline Benjamin GovedarovicFriend
Messages: 3
Registered: May 2021
Junior Member
I'm trying to make a 1.8.9 mod but I don't know what version to use. Do you know any?

[Updated on: Wed, 02 June 2021 09:45]

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Re: Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841896 is a reply to message #1841886] Wed, 02 June 2021 13:23 Go to previous messageGo to next message
Ed Merks is currently offline Ed MerksFriend
Messages: 31955
Registered: July 2009
Senior Member
My guess based on Googling this stack trace is that the library you are using does not work with Java 9 or higher because it assume the class loader is a URL class loader. So you either need something newer or run with Java 8.

Ed Merks
Professional Support: https://www.macromodeling.com/
Re: Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841954 is a reply to message #1841896] Fri, 04 June 2021 08:45 Go to previous messageGo to next message
Benjamin Govedarovic is currently offline Benjamin GovedarovicFriend
Messages: 3
Registered: May 2021
Junior Member
I don't know what I did different but my Eclipse Mars worked and when I ran the java file Minecraft opened so I guess it was the version of Eclipse.
Re: Im new to minecraft coding and I tried to open the game with run and this error poped up [message #1841956 is a reply to message #1841954] Fri, 04 June 2021 10:09 Go to previous message
Ed Merks is currently offline Ed MerksFriend
Messages: 31955
Registered: July 2009
Senior Member
Probably your old Mars IDE was using an older JVM and that JVM became the default JRE used in the workspace. Compare what's in Window -> Preferences -> Java -> Installed JREs.

Ed Merks
Professional Support: https://www.macromodeling.com/
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