In some cases, the installation is unable to proceed. In other cases, PDF Exports in the entire instance are broken. Each attempt results in the following exception being thrown:
Prior to that, the following Error appears:
At first glance, the problem looks to be a missing or incorrect class being referenced in Confluence; specifically, the prime suspect is the fop jar in the /confluence/WEB-INF/lib directory.
The issue stems from the missing AWT LibrayAlthough the error message asked to check that Headless mode is enabled, this is actually already enabled by default in the*setenv.sh of standalone Confluence distributions. The conclusion here is that the problem is called by the missing X11 libraries.
A missing resources for the JDK, specifically libXp.so.6 from the deprecated X11 rpm.