Unable to start minecraft server Ubuntu 20.04

Technical Support
1

OS Name/Version: Ubuntu 20.04

Product Name/Version: AMP ‘Triton’ 2.3.3.0

Problem Description:

I’ve installed AMP on latest version of Ubuntu. Whenever I create a instance of minecraft java It just says Unable to start server when I try to start server in the manage tab. I receive this message: The Minecraft server stopped within 5 seconds of starting, this is not a fault with AMP - you should check your Minecraft servers log files to find out why it is unable to start.
I am fairly new to this so some guidance would be appreciated.

Steps to reproduce:

  • Step 1 Create New Minecraft Java Instance
  • Step 2 Clicked on manga tab next to stop instance
  • Step 3 Clicked start. I also have tried clicking update.

Actions taken to resolve so far:
I had an issue where the instance would not start either but that has been resolved. I have not come across anything to try.

2

What does the console for that instance say? Did you check the logs as it suggests?

3

I’m not sure how to check that.

4

You click the console tab on the left side of that instance after trying to start it :slight_smile:

5

Console

01:53:51

Error: LinkageError occurred while loading main class net.minecraft.bundler.Main

java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 60.0

6

Make sure Java 17 is installed and selected within AMP.

7

Is there an easy way to install Jav17? I’m having issues.

8

https://adoptium.net/ is the recommended version for use with AMP.

9

I think I have it installed. How do I hook it up with AMP?

10

Just restart the Minecraft instance and it will pick it up :slight_smile:

11

Maybe I did not install java? server will still not start.

12

run java -version. It will tell you what your current default java is. If the command is not found, then you do not have java installed.

13

openjdk version “16.0.1” 2021-04-20
OpenJDK Runtime Environment AdoptOpenJDK-16.0.1+9 (build 16.0.1+9)
OpenJDK 64-Bit Server VM AdoptOpenJDK-16.0.1+9 (build 16.0.1+9, mixed mode, sharing)

So I have the wrong version

14
15

I now have the correct version of Java. Server still does not start.
openjdk 17.0.2 2022-01-18
OpenJDK Runtime Environment (build 17.0.2+8-86)
OpenJDK 64-Bit Server VM (build 17.0.2+8-86, mixed mode, sharing)

command window:
Error: LinkageError occurred while loading main class net.minecraft.bundler.Main

java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 60.0

16

Make sure that the newer version is actually selected in AMP in the java settings.

17

Thank you guys so much. It was able to start now