When creating maven project using Intellij IDEA, by default target directory is not visible in Project explorer. But I can make it visible by removing it from excluded folders in module settings. But it work only for short period of time, and after 10-15 minutes target directory again invisible. So I need again go to module settings and remove target directory from Excluded directories.
How I can make visible maven's target directory forever?
Try to uncheck the Exclude build directory checkbox under Settings - Project Settings - Maven - Importing.
Description from IDEA help:
Select this check box to exclude a build directory from the project. This might be useful, if you want to speed up the project's importing process . If this check box is cleared, IntelliJ IDEA will index files in the build directory every time you import a project which might take additional time.
In IDEA version 14 or higher you can try to uncheck "show excluded files" in the project panel set. It is checked by default. I found this solution here.
This can be directly configured in File -> Project Structure -> Modules -> {select your module} -> Sources
There you will see which folders are excluded from being shown in Project explorer. Just remove the "target" from the exclusion list and it will be shown from that moment on.