Using SkipListener which implements Ordered with scope="step": No context holder available for step scope - listener

Question

When using a skipListener with scope="step" which implements Ordered I get the following exception:
Error creating bean with name 'scopedTarget.scopedTarget.fisalisBatchMeldungenListener': Scope 'step' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton; nested exception is java.lang.IllegalStateException: No context holder available for step scope
If I don't let my listener implement Ordered the exception does not ocure.
Here is my Bean Definition:
<bean id="erzeuger" class="...." scope="step">
<property name="user" ref="user" />
<property name="termin" ref="termin" />
<property name="services" ref="services"
</bean>
<bean id="listener" class="Listenerclass" scope="step">
<property name="erzeuger" ref="erzeuger" />
</bean>
And here is the part where I am using it:
<step id="myStep" parent="abstractBatchStep" xmlns="http://www.springframework.org/schema/batch">
<listeners merge="true">
<listener ref="listener" />
</listeners>
</step>
Has anyone an idea where the problem is?

Answer 1

I have the point:
When the Listener is added to the step, the step checks, if its implements Ordered. If it does, the step adds the listener to a collection which will be immediatly sort by using a comperator. This comperator invokes getOrder(9 on the instance of the listener. But if the listener ist stepScoped, the SpringBatch Factory (s. comment below) has to return the "real" bean instance. But at this point the "real" bean instance does not exist.
For sope="step" read this:
Scoped bean works in different manner. When context is created this bean is wrapped into additional proxy object (by default created by CGLIB), which is passed to the bean that refers it (this proxy is by default singleton, e.g. shared). So each time the method is invoked on the proxy in runtime Spring intersects the call, requests the factory to return the instance of the bean and invokes the method on that bean. The factory in its turn may lookup for "real" bean instance e.g. in HTTP request ("request" scope) or HTTP session ("session" scope) and/or create new instance if necessary. Late instantiation allows to initialize the scoped bean with "runtime" (scope) values, e.g. values from HTTP request/session which are obviously undefined when context was created. In particular "step"-scoped beans are bound to thread local (remember that steps are run in parallel for partitioning). So, scoped beans are dereferred when you call a method on them. Finally one can easily break this elegant Spring "ideology" by calling any method on scoped bean just after it is set to another bean (e.g. in the setter) :)