You don't have to add each class individually to the black list. They are all regex
patterns, so just do this:
<extend-configuration-property name="rpc.blacklist"
value="com.google.gwt.user.client.ui.*Collection"/>
In my case I wanted even finer grained control over which collections get included,
so I did this:
<extend-configuration-property name="rpc.blacklist" value="-.*List"/>
<extend-configuration-property name="rpc.blacklist" value="-.*Map"/>
<extend-configuration-property name="rpc.blacklist" value="-.*Collection"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.HashMap"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.LinkedHashMap"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.ArrayList"/>