Spring bean instantiation exception for collection

Spring is throwing the following exception when it tries to instantiate a bean which implements AbstractSet<Channel>.

Cannot create copy of Collection type [org.jboss.netty.channel.group.DefaultChannelGroup] - injecting original Collection as-is

<bean id="defaultChannelGroup" class="org.jboss.netty.channel.group.DefaultChannelGroup" scope="prototype"></bean>

<bean id="client" class="com.menacheri.Client">
   <property name="id" value="6"></property>
   <property name="gameRoomChannelGroup" ref="defaultChannelGroup"></property>
</bean>

Any id开发者_StackOverflow社区eas on what I am doing wrong?

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Spring 3.0.5 seems to have a bit better error messages, I can't find the one you've provided. Here are the possible reasons (errors from Spring sources):

• Collection of type [] returned null Iterator
• Cannot access Collection of type [] - injecting original Collection as-is
• Cannot create copy of Collection type [] - injecting original Collection as-is
• Collection type [] seems to be read-only - injecting original Collection as-is

Nevertheless, try wrapping the collection you are trying to inject in a new, fresh one, like this:

<bean id="wrappedSet" class="java.util.HashSet">
    <constructor-arg>
        <ref bean="defaultChannelGroup"/>
    </constructor-arg>
</bean>

...and inject wrappedSet instead. Might help, just a guess.