It is comming from this: DebugInfoStackFactory.printVirtualTaskStackTrace(new PrintWriter(System.out), task, false, false, false);
Index: frysk-core/frysk/debuginfo/ChangeLog 2007-09-07 Andrew Cagney <cagney@redhat.com> * TestTypeEntry.java: Delete stray System.out output. * TestFrameDebugInfo.java: Delete stray System.out output.