Exception - Problem building schema in the BPEL assign activity in JDeveloper 11g during design time

Error:  Assume you have a BPEL project in SOA 11g which has multiple external WSDLs and adapter connections.  Let us say you have created a DB adapter connection for a SELECT operation from a database table then Schema, wsdl generated properly.  But you may see the Exception - Problem building Schema in the assign activity as shwon in the below image.

Solution:  In most of the cases the namespace is not properly placed.  Bus sometimes even the namespaces and all other references related DB adapter looks fine, but still we see the error. The reason behind this error is JDeveloper is not able to reach the schema building due to some other unexpected errors.  So the JDeveloper is not able to form the proper Element structure of the complex messages/elements.

If you have changed any WSDL URLs in the composite.xml  (specially host names to point to a new systems which is active while you are working) then make sure that the host also changed in the corresponding .componentType  file.  If this is not changed then the WSDL partnerlink not able to reach the target schema details, so it will fail to build all the other complex elements as well.

So to fix this, make sure that all the endponts are reachable while compiling/building the BPEL processes.