what I have done:
Download from https://www.oracle.com/tools/downloads/sqldev-downloads.html
unzip
First time run sqldeveloper.exe everything works well and I created some user then closed sqldeveloper.
When the second time I run sqldeveloper.exe after lunch, the screen as following shows up for about 5 seconds, then it's gone like nothing happened. there is no error shown up and no log I can find.
Please let me know if there is anything I can do about it.
Thank you ,really need help.