Question

When a service call returns null (NullPayload) the proxy generated for the component binding throws a ClassCastException. Should it return null instead? (This is in Mule CE 3.2.1) See MULE 4405

Thanks

Here is the mule config:

<mule ...>

    <flow name="entryPoint">
        <vm:inbound-endpoint
            path="entryPoint"
            exchange-pattern="request-response" />
        <component class="classcastexception.Component">
            <binding interface="classcastexception.Interface" method="foo">
                <vm:outbound-endpoint
                    path="classcastexception.Interface.foo"
                    exchange-pattern="request-response" />
            </binding>
        </component>
    </flow>

    <flow name="classcastexception.Interface.foo">
        <vm:inbound-endpoint
            path="classcastexception.Interface.foo"
            exchange-pattern="request-response" />
        <component class="classcastexception.InterfaceImpl" />
    </flow>

</mule>

The java classes are:

Interface.java

package classcastexception;

public interface Interface {

    String foo(String s);

}

Component.java

package classcastexception;

public class Component {

    private Interface i;

    public String foo(final String s) {
        return i.foo(s);
    }

    public void setInterface(final Interface i) {
        this.i = i;
    }

}

InterfaceImpl.java

package classcastexception;

public class InterfaceImpl implements Interface {

    @Override
    public String foo(String s) {
        return null;
    }

}

Answer 1

This bug has been recently fixed. Take a look at the MULE-6287 jira for more information. As you can see this fix will be included in the soon to be released mule 3.3.