After updating to 2020.1, I can't run my programs (Error:java: error: release version 15 not supported)

Hi,

Please check whether you have correct JDK version in the following places:

1. The "Project SDK" and the "Project language level" in File | Project Structure | Project.
2. The "Language level" in File | Project Structure | Modules | Sources.
3. The bytecode version in File | Settings| Build, Execution, Development | Compiler | Java Compiler.

If it's a Gradle or Maven project, it may have the release version specified incorrectly somewhere in the build file. There is no public release for Java 15 yet, so you can't target it. Could be a typo that someone has specified 15 instead of 1.5.

Hello,

I checked and all 3 are on Java 14, which is the only version I have on this computer, which is new.

I don't understand why the error message mentions Java 15.
I tried running again, and still get Error:java: error: invalid source release: 15

Do you have any other idea what could be wrong?

Is that a Maven or Gradle project?

If yes, please check your project `pom.xml` or the `build.gradle` file to see whether you have set the JDK (or something like Compiler/ sourceCompatibility/targetCompatibility version) 15 in there and change them to 14.

Please see https://stackoverflow.com/a/12900859/104891 . It could be that you have 15 specified somewhere in the build file instead of 1.5.

Lejia Chen Hi, no, it's not a Maven nor a Gradle project

I restarted IntelliJ this morning and got this error message right away when it restarted:
07:21 Plugin Error: Plugin "IntelliJ Light Theme" is incompatible (until build 201.0 < IC-201.6668.121).

I also received that message as soon as it had updated and restarted yesterday.
Do you think that has anything to do with the issue (I use the dark theme)?

Serge Baranov Hi, everything is set on 14 for this project, Intellij doesn't even have 15 to suggest (nor 1.5, just 5 directly written).
I have no clue where this 15 in the error message is coming from.

Maybe I should just uninstall and reinstall IntellijIdea ?

> I restarted IntelliJ this morning and got this error message right away when it restarted:
07:21 Plugin Error: Plugin "IntelliJ Light Theme" is incompatible (until build 201.0 < IC-201.6668.121).

There is the same bug logged in our issue tracker: https://youtrack.jetbrains.com/issue/IDEA-238150. You could just remove this plugin in `Preference/Settings | Plugins`.

For the 15 error issue, could you try to back up your project firstly, remove the `.idea` directory and the `iml` file in your project, and use `Open or Import` from the "Welcome to IntelliJ IDEA" window to reimport this project again.
Also, could you share your project (or a sample ) for the investigation? You could upload your project here: https://uploads.services.jetbrains.com/

Please see https://intellij-support.jetbrains.com/hc/en-us/community/posts/360008168219-error-java-error-release-version-15-not-supported?page=1#community_comment_360001629140 .

Hi Lejia,

It worked; I disabled the light theme, and removed the .idea dir and .iml file and now my project works fine.
Thank you very much for your help!