sun.font.FontManager.getDefaultPlatformFont exception

Im using Openshift Platfrom (jre 1.6) to deploy my java application with jasper reports. From last few days Im receiving following exception during jasper report execution.

java.lang.NullPointerException    sun.font.FontManager.getDefaultPlatformFont(FontManager.java:3409)    sun.java2d.SunGraphicsEnvironment$2.run(SunGraphicsEnvironment.java:263)    java.security.accessController.doPRivileged(Native Method)    sun.java2d.SunGraphicsEnvironment.<init>(SunGraphicsEnvironment.java:164)
any info how to resolve this issue?
Our sysadmins had updated java to java version "1.6.0_39" OpenJDK Runtime Environment (IcedTea6 1.13.11) (rhel-1.13.11.1.el6_8-x86_64) OpenJDK 64-Bit Server VM (build 23.25-b01, mixed mode)
on linux version 2.6.32-573.7.1.el6.x86_64 (mockbuild@x86-031.build.eng.bos.redhat.com) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-16) (GCC) ) #1 SMP Thu Sep 10 13:42:16 EDT 2015
I got around that problem by installing these with yum
dejagnu.noarch 1:1.4.4-17.el6dejavu-sans-mono-fonts.noarch 2.33-1.el6dejavu-serif-fonts.noarch 2.33-1.el6