IntelliJ Idea does not start after the update to ideaIC-2021.2.3

You need to run the IDE via bundled runtime: https://intellij-support.jetbrains.com/hc/en-us/articles/206544879-Selecting-the-JDK-version-the-IDE-will-run-under

Try to unset JAVA_HOME 

Thanks for the quick response.

Unset did not help:

$ unset JAVA_HOME
$ echo $JAVA_HOME

$ idea/idea-IC-212.5457.46/bin/idea.sh
Error occurred during initialization of VM
java.lang.UnsupportedClassVersionError: com/intellij/util/lang/PathClassLoader has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

I have tried to install Idea with the jetbrains-toolbox, but the result is the same.

The steps described in the link that you have suggested have not helped because there is no <product>.jdk file. I think that happens because the Idea does not start.

$ ll ~/.config/JetBrains
ls: cannot access '/home/myuser/.config/JetBrains': No such file or directory
$ ~/.local/share/JetBrains
bash: /home/myuser/.local/share/JetBrains: No such file or directory
$ ~/.cache/JetBrains
bash: /home/myuser/.cache/JetBrains: No such file or directory
$ ~/.cache/JetBrains
bash: /home/myuser/.cache/JetBrains: No such file or directory

May you run this script with "--path <path to idea.sh file>" as an argument and share the repair.log generated? 

You can download the report from here.

Please try running again with runtime aspect: 

repair --path=<path> runtime

Where this repair comes from?

This solved my issue:

idea.sh

...

# ---------------------------------------------------------------------
# Run the IDE.
# ---------------------------------------------------------------------
echo $JAVA_BIN
JAVA_BIN=/usr/lib/jvm/jdk-11.0.4/bin/java
echo $JAVA_BIN

...

I have some strange warning, but at least IntelliJ starts:

/usr/lib/jvm/java-8-oracle/bin/java
/usr/lib/jvm/jdk-11.0.4/bin/java
./idea.sh: 158: ./idea.sh: exco: not found
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.intellij.util.lang.UrlClassLoader (file:/home/myuser/applications/idea/idea-IC-212.5457.46/lib/util.jar) to field java.lang.ClassLoader.classLoaderValueMap
WARNING: Please consider reporting this to the maintainers of com.intellij.util.lang.UrlClassLoader
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
2021-11-08 23:46:28,129 [ 29499] WARN - tor.impl.FontFamilyServiceImpl - Couldn't access required runtime API, will fall back to basic logic of font selection

I have no idea why IntelliJ picks up java 8 from my disk...

This is so weird. I had no problem with the previous version.

I had the same problem. Unsetting JAVA_HOME from the console is of no use (I have JAVA_HOME to set 1.8 set  in user .profile because of other apps). The Java detection mechanism in new IDEA is weird.

The following helped:

export IDEA_JDK=/usr/lib/jvm/java-11-openjdk-amd64

which I set in a wrapper script before running idea.sh.

Marek Bezpalec You should not override the bundled JetBrains Runtime. Please see https://intellij-support.jetbrains.com/hc/en-us/articles/206544879.