I've downloaded and unpacked Oracle's SQL Developer 19.4 on macOS 10.15 Catalina. During the first start up, the usual warning appears, which I clicked away as I do since a number of years: SQL Developer starts ok. When creating a new connection to an Oracle database, I enter all the detail and it works fine (the 'Test' button says it's ok. Previously, only JDK 8 worked with Oracle SQL Developer. But, per JDK 8 or 11 are required. (there is some misleading documentation that says JDK 8 or higher, but it must be 8 or 11). Also, per Oracle, JDK 11.0.7 is certified for Mac OS Catalina. I’m running SQL Developer 14.1.3.20.78 on Mac OSX El Capitan 10.11.5, Java SDK 1.8.092 installed; The program works, but extreeeeemely slow, as in “not working”. When I click something, the program seems to have problems “drawing” the objects.
After upgrading to macOS Big Sur I couldn’t run Oracle SQL Developer. I got the following error: The application “SQLDeveloper.app” can’t be opened
To resolve this issue I got help from Kris Rice and Niels de Bruijn. The issue is caused by Apple and the Java applet plugin.
Here’s how I got SQL Developer working:
The one that caused the problem is the 'Oracle Corporation' - 'Java' /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home
and you’ll need to remove it.
If you run SQL Developer now it should work. I’m not sure about the side effects of removing this Java applet plugin. If I find it to be critical to other things I’ll be sure to update this post.