How to switch to debug mode without application re-deploy in Intellij Idea for Weblogic?

1. Open file in Notepad
../{your_weblogic_folder}/user_projects/domains/{your_domain_name}/bin/setDomainEnv.cmd

2. Set the following value for JAVA_DEBUG variable, line will look this way:
set JAVA_DEBUG=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,address=50000,server=y,suspend=n

where 50000 is any port number you wish to use for debug.

3. In Intellij Idea Run -> Edit Configuration ->click + and add 'Remote' configuration.

4. Configure Remote configuration: add 'Name', set 'Port' number, the same you have indicated in point 2.

Run application in regular mode and when needed switch to debug.