Trouble Starting Forge Server for Minecraft 1.20.1

[Redempsyn]

Hello,

I am trying to start my forge-modded server. I go to the point of invoking the run.bat, but I get the following error:

java.lang.IllegalArgumentException: Unsupported class file major version 66

I have Java SE Dev Kit 22.0.1 installed. Do I need to downgrade? 

Before starting a Forge dedicated server, I created a vanilla server. I did get an error when trying to connect, but I figured it was because I had mods running on the client. 

Sadly, I am pretty much "unconscious incompetent" here. 

 

Thanks for any advice. 

Edited May 4 by Redempsyn
Stated wrong Java version installed and added details

[Xoroshio]

Hello there,  you have the wrong Java version and you need to update not downgrade. I hope this helps

[TileEntity]

Minecraft 1.20.1 requires Java 17 to work

[Redempsyn]

Hi Guys,

Thanks for the replies. From what I can see I have the latest version of Java. I have Java 8 update 411 and Java SE Development Kit 22.0.1. It was late for me and I meant 22.0.1 not 11.0.1. Should I only have one installed? 

 

Thanks again!

 

Edited May 3 by Redempsyn
Clarity

[Xoroshio]

Try and uninstall both and get Java 17

[TileEntity]

You can have multiple Java version installed

 

For the server, you have to set the path to java 17 in your startscript

For example:
 

"C:\Program Files\Java\jdk-17.0.9\bin\javaw.exe" -Xmx4G -Xms2048M -jar forgeserver.jar 
pause 

Just make sure the path is correct and keep the quotation marks

And the forgeserver jar name should match

[Redempsyn]

Hi Guys,

Thanks again for the replies. Uninstalling version 22 fixed my issue. I tried starting the server using the suggestion @TileEntity gave but could not see how to invoke Forge. I then uninstalled JDK version 22 as @Xoroshio advised. I may have to stay with having only JDK 17 installed. Now I need to figure out why the startup does not like the number of mods I installed. 

[Xoroshio]

you probably need to give it more RAM