Java path especified in /usr/local/openfire/bin/openfire.sh
permissions in /usr/local/openfire folder and subfolders.
How to make it works:

Install JDK
Install XAMPP
Install openfire 4.2.2 (in my case)
look for your java path (you can open a console and use: /usr/libexec/java_home)
modify the permissions for folder and sub folder of /usr/local/openfire/ to read/write
open the file openfire.sh (located in /usr/local/openfire/bin/)
6.1. change the java path home for the real one in the line: JAVA_HOME=