Is there a way to set message headers from a bean?

In Spring XML DSL, it would be something like

 <setHeader headerName="headerName">
      <method bean="mybean" method="mymethod" />                
</setHeader>

Another way in XML:

<setHeader name="headerName"> 
    <simple>${bean:yourBean.getMethod}</simple>           
</setHeader>

Certainly! One of the options available is

.setHeader("headerName").method(beanInstance, "methodToGetHeaderValue")

Using this approach, the method (say, methodToGetHeaderValue) on the provided bean instance will return a value, and that will become the value of the header.

There are a number of options available. You can call it with a bean instance, a bean class (like in your example), or even a bean name, all with or without a method name.