It happens, that each time when I push MacOS High Sierra regular updates, my JDeveloper does not start any more. The fix looks very simple, just need to delete JDeveloper system directory. Sounds frightening, but do not be confused because of naming. By fact it is just operational directory where JDeveloper keeps various temporary and configurational stuff. It is even not created on install, but instead – on the very first run. If you delete it, it is just created again. By default it is located:
[USER_HOME]/.jdeveloper/system12.2.1.0.42.151011.0031
Depending on your JDeveloper version and installation, you’ll have different numbers in directory name. But it will start as “system…” anyway.
In case you’re a Windows user and experiencing similar issues, then its default location under Windows is:
[USER_HOME]\AppData\Roaming\JDeveloper\system12.2.1.0.42.151011.0031
So, delete it. Now JDeveloper should startup.
But… It would be quite ok this kind of workaround, unless you lost all of your custom JDeveloper settings and preferences… How to deal with that, check here:
How to keep custom JDeveloper preferences after deleting its system folder?
JDeveloper Version 12.2.1.0.0