Java: How to tell which fontconfig file my system is currently using?

Question

I am trying to debug a font-related issue in a third-party Java application. Specifically, ChemAxon JChem. I've been consulting this guide: http://java.sun.com/j2se/1.5.0/docs/guide/intl/fontconfig.html

Part of the problem, is that I'm not sure which fontconfig.properties.src file my Java setup is currently referencing.

Here are my fontconfig files:

$ ls fontconfig*src 
fontconfig.Fedora.properties.src  fontconfig.properties.src   
fontconfig.SuSE.properties.src  fontconfig.Ubuntu.properties.src

My system is a CentOS system, so I imagine it is probably either ferencing the default fontconfig.properties.src file or the fontconfig.Fedora.properties.src file, since CentOS and Fedora are both derived from Red Hat.

So, can I definitively tell which fontconfig file my system is using?

Thanks,

-John David

Answer 1

The JRE class sun.awt.FontConfiguration already has logging for this, you just need to enable it.

• Add this option to Java -Dsun.java2d.debugfonts=true
• Edit jre/lib/logging.properties

Change this line

java.util.logging.ConsoleHandler.level = ALL

Add this line

sun.awt.FontConfiguration.level = ALL

And you'll then see a line like this in your stderr (logger uses stderr for some reason)

CONFIG: Read logical font configuration from /your/path/jre/lib/fontconfig.RedHat.6.bfc

Answer 2

Just use strace to check which of those files is successfully opened:

$ strace -f -e open java ... 2>&1 | grep fontconfig
[pid  3321] open("/usr/java/jdk1.7.0_55/jre/lib/fontconfig.RedHat.6.bfc", O_RDONLY|O_LARGEFILE) = 115

If this doesn't tell you which file it is using, chances are that it is using system wide fonctconfig instead. You will get an output starting like this then:

[pid  3259] open("/usr/java/jdk1.7.0_55/jre/lib/i386/xawt/libfontconfig.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid  3259] open("/usr/java/jdk1.7.0_55/jre/lib/i386/xawt/../libfontconfig.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid  3259] open("/usr/java/jdk1.7.0_55/bin/../lib/i386/jli/libfontconfig.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid  3259] open("/usr/lib/libfontconfig.so.1", O_RDONLY) = 116