I am using spring WebServiceTemplate as a web service client programmatically i.e. without instantiating a spring container. I am using Jaxb2Marshaller for marshaling/unmarshaling. In my application, I create a single instance of the SaajSoapMessageFactory and one instance of Jaxb2Marshaller. I also create a single instance of the WebServiceTemplate and assign the previously created instances of SaajSoapMessageFactory and Jaxb2Marshaller.
The WebServiceTemplate I created is used in a multi threaded way i.e. multiple threads can call marshalSendAndReceive at the same time. My question is - is my configuration thread safe? I am concerned about the Jaxb2Marshaller. The javadoc says Jaxb2Marshallers are not necessarily thread safe. How can I use the Jaxb2Marshaller in a thread safe way without reinitializing the Jaxb context?
As an aside: looking at the example spring-ws configuration in the spring reference leads me to believe that the Jaxb2Marshaller is thread safe but the Javadoc seems to contradict that.
The javadoc for Jaxb2Marshaller makes no mention of thread-safety one way or another, so I'm not sure why you think it's not. If it wasn't thread-safe, the javadoc would say that very clearly.
Your configuration of WebServiceTemplate, SaajSoapMessageFactory and Jaxb2Marshaller singletons is perfectly fine, and entirely thread-safe.