In the following code : String test = "[a|b|c]"; System.out.println("+++ " + test); logger.log(Level.SEVERE, test); output is : +++ [a|b|c] [a The pipe character and the following characters are not printed. I tried doubling it ||, escaping it \|, enclosing it '|', using the unicode char \u007c, none of them work. I'm using log4j-1.2.14.jar but I tried log4j-1.2.16.jar and the issue is still present. Maybe | has a special meaning and displaying it requires something special. Any idea ? Thanks in advance !