unicode characters appear as question marks in IntelliJ IDEA console

Is the file encoding configured correctly? See that "Settings | File Encodings" uses UTF-8. Printing ♠ works for me when I have IDE encoding and all files set to UTF-8. Recompiling may be needed after changing the encoding.

System.out uses the default encoding of the underlying operating system which typically is ISO-8859-1 or UTF-8. The first is what I have with the 1252 codepage under XP.

Is this in a CMD.EXE window, or inside an IDE?

A little update for the year 2015

TL;DR answer:

Go to Settings -> Editor -> File Encodings -> Project Encoding and set it to "UTF-8".

Expanded answer:

The reason why it does not work can be found by placing a breakpoint on a System.out.print() call. When the breakpoint hits, you can add System.out to Watches, and you can see that System.out.textOut.out.se.cs is set to windows-1252 or something similarly unsuitable.

The setting which magically worked for me (I do not know why) is in Settings -> Editor -> File Encodings -> Project Encoding. You need to set that to "UTF-8".

Then, unicode characters display properly on the console, and one more quick look with the debugger shows that the value of System.out.textOut.out.se.cs has magically turned into UTF-8.

I am saying "magically" because I do not see how and why an editor setting should affect the character set that System.out gets instantiated with when launching/debugging an application. If someone knows what is the logic behind this, please do tell!

Go to Help > Edit Custom VM options... then add the following option:

-Dconsole.encoding=UTF-8
-Dfile.encoding=UTF-8

I'm not sure if both are necessary but it worked for me. You need to restart IntelliJ for changes to be applied.

I had already tried changing every encoding setting in Intellij, setting those options in Gradle and changing the system encoding, this is the only one that worked.