As the title clearly describes, some UTF-8 characters such as (ğ, ç, ş, etc.) could not be displayed on the console output despite (1) setting all the encoding preferences available in the Settings UI to UTF-8, and (2) adding the -Dfile.encoding=UTF-8 parameter to the idea64.exe.vmoptions file as it is provided in another question in Stack Overflow.
IntelliJ IDEA Version: 2018.3.5 (Ultimate Edition)
Edit: I am running my web app in debug mode, and using Apache Tomcat as the servlet container. So, the console output is the log of the web app.
183.5153.38 version is an example.
Your IntelliJ IDEA Ultimate runs AppData \ Local \ JetBrains \ Toolbox \ apps \ IDEA-U \ ch-0 \ 183.5153.38 \ bin \ idea.exe.