The class com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl in rt.jar is returning a null document when it is parsing an xml document. The document : common-uielements.xsl is attached.
This problem occurs only with jdk 1.6.0_15-b03 and above including the latest publicly available jdk 1.6.0_16 version.
jdk1.6.0_13-b03 did not have this problem. Did not test with jdk 1.6.0_14 due to lack of access to this version immediately.
This issue causes our product : Communication Express 6.3 to become unusable.