In one of my proxies message flow, I have come across the following error with one of the assign activities, when I use the XSLT to do some processing on the payload.
javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: Content is not allowed in prolog.
When I add/delete a single character in the payload, the XSLT will work without any problem. I observed this issue in OSB 11.1.1.3 on Linux platform.
On searching the internet, found several workarounds:
– Adding <?xml version=’1.0′ encoding=’utf-8′?> to the payload
– Verifying for malformed characters at the beginning of XML payload
– Rewriting the XSLT etc..etc..
None of the above options had really worked for my case. Finally found a patch#10086559 in oracle support site and applying this patch resolved the issue.
Have seen the same issue in OSB 11.1.1.4 and resolved after the patch application. Have not verified this issue in recently released OSB 11.1.1.5.
Siva's Blog 
Hi Siva,
I am facing same error “Content is not allowed in prolog.”
Can you advise where can i find details about patch#10086559 in oracle support site.
Thanks,
Jay
You can get the details in support.oracle.com. Just search the knowledge base with this patch#. Facing the issue in linux env??