When is a Boolean not a Boolean?

You have to be careful doing the obvious thing sometimes because it doesn’t always give you the result to want. For instance, I had a requirement to add a header to a message generated in an Apache Camel route. Seemed simple to be so I added this:

<setHeader headerName="NEW_HEADER">
    <constant>true</constant>
</setHeader>

The hidden issue with this is that the header will be a java.lang.String and it will have the value of “true”. Now in many situations that’s not a problem, however the upstream system for me cared about whether this was a java.lang.String or a java.lang.Boolean. The fix is pretty simple though. You just tell Camel what the return should be using a simple expression. Like this:

<setHeader headerName="NEW_HEADER">
    <simple resultType="java.lang.Boolean">true</simple>
</setHeader>