How to keep custom JDeveloper preferences after deleting its system folder?

Time to time it happens, that JDeveloper stops working for some reason. It just not open or behaviour become unstable. The fastest and easiest fix is to delete its system folder. Which is like a temporary one, created on the very first run of JDeveloper. There it keeps various cache information and settings. Among those settings there are user preferences made by adapting IDE to personal needs. It could be code formatting styles, shortcut keys or whatever can be tweaked through JDeveloper -> Preferences menu. Also resource configuration, like DB or application server connections are kept in this folder as well.

For example most important for myself are key shortcuts, which I always try to align between IDEs I’m using (i.e. with IntelliJ IDEA).

So, once your JDeveloper stops functioning and refuses to startup, try to delete system folder, which is usually located:

Mac OS

[USER_HOME]/.jdeveloper/system12.2.1.0.42.151011.0031

Window

[USER_HOME]\AppData\Roaming\JDeveloper\system12.2.1.0.42.151011.0031

All of those digits in the folder name will differ in your enviroment, but the name will start as “system” for sure. And folder “.jdeveloper” will be a hidden one (at least in Mac OS).

Steps to proceed:

• Make a backup of these folders:
  • …/system12.2.1.0.42.151011.0031/o.ide (i..e. shortcut key map is saved here)
  • …/system12.2.1.0.42.151011.0031/o.jdeveloper (Code formatting settings, …)
  • …/system12.2.1.0.42.151011.0031/o.jdeveloper.rescat2.model (Database, application server connections, …)
  • …/system12.2.1.0.42.151011.0031/system_cache (Current window layout, opened applications, other real time operational configuration, …)
  • [Maybe some other which make sense to you]
• Delete your “/system…” folder and try to startup JDeveloper again.
• Close JDeveloper.
• Put back backuped folders “o.ide” and “o.jdeveloper” to newly generated system folder. Just replace them. Make sure JDeveloper is closed meanwhile.
• Start JDeveloper again.

Most of your custom JDeveloper preferences should be back again. Although if you miss something, can make a backup of whole “system…” folder, then make a comparison of it with a new one. You should identify other configuration files which make sense to you. You could even put back whole system folder back and it might work out, depends on what was the cause of JDeveloper crash. For example I’m constantly experiencing not opening JDeveloper after each regular macOS HighSierra OS update. In this case for me it is enough just to put back whole “system…” folder with all of its contents.

Actually this approach is just for emergency recovery. If you need to migrate settings from one JDeveloper instance to another, there is a dedicated functionality. When you start a fresh copy of JDeveloper it asks whether to migrate settings from previous version or not.

Depending on your JDeveloper version there some possibilities to export some preferences manually. Some of them are introduced in this post by Timo Hahn.

JDeveloper Version 12.2.1.0.0