How do I improve performance of application that uses the JAXBContext.newInstance operation?

I use the JAXBContext.newInstance operation in my JBoss based web application. This operation, as I understand, is very heavyweight. I only require two unique instances of the Marshaller class.

My initial proposal is to have a static initializer block that will initialize these two instances only once upon the class loading:

public class MyWebApp {
    private static Marshaller requestMarshaller;
    private static Marshaller responseMarshaller;

    static {
        try {
            // one time instance creation
            requestMarshaller = JAXBContext.newInstance(Request.class).createMarshaller();
            responseMarshaller = JAXBContext.newInstance(Response.class).createMarshaller();
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }

    private void doSomething() {
            requestMarshaller.marshall(...);
            responseMarshaller.marshall(...);
            ...
    }

}

If this is a reasonable solution then I guess I'll have answered my own question, but I would like to know if this is the correct way to do this?