This error is caused by Eclipse using JDK17 instead of JDK when trying to load Minecraft 1.12.2
JDK17 is used by our 1.18 courses, while our 1.12.2 courses use a copy of JDK 8 called JDK.
To fix this, you need to tell Eclipse to use the right JDK.
1. Open your project in Eclipse if it isn't open already.
2. Right click on JRE System Library and hover over Build Path
3. Click Configure Build Path
4. In the next screen, make sure JRE System Library is selected and then click Edit.
5. Next click Installed JREs
6. On the next screen, click Add
7.Make sure Standard VM is select and then click Next
8. On the next screen, click Directory
9. This issue is specific to Windows, so the JDK will be located at: C://Users/USERNAME/CodaKid/Dependencies/jdk where USERNAME is your computer's username. Then click Okay.
10. Click Finish.
11. Select the checkmark next to JDK and then click Apply and Close
12. Click Workspace Default JRE and then Finish.
13. Click Apply and Close and you should be all done.