New issue 722 by wix...@gmail.com: PrivateModule prevents interceptors to  
be applied
http://code.google.com/p/google-guice/issues/detail?id=722

Description of the issue:
When an interceptor is bound inside a private module the original class  
will not be enhanced if its bound and exposed via an interface. If the  
class is bound and exposed directly or if the interface is bound in a non  
private module the interceptors are applied correctly. This seems incorrect  
and an inconsistent behavior.

Steps to reproduce:
1. run all 3 unit tests in attached InterceptorTest class
2. testPrivateModule fails, but the other 2 run fine

Attachments:
        InterceptorTest.java  2.7 KB

Comment #1 on issue 722 by wix...@gmail.com: PrivateModule prevents  
interceptors to be applied
http://code.google.com/p/google-guice/issues/detail?id=722

Probably related to issue702

Comment #2 on issue 722 by wix...@gmail.com: PrivateModule prevents  
interceptors to be applied
http://code.google.com/p/google-guice/issues/detail?id=722

upload new test without the @Ignore annotation

Attachments:
        InterceptorTest.java  2.6 KB

Comment #3 on issue 722 by sberlin: PrivateModule prevents interceptors to  
be applied
http://code.google.com/p/google-guice/issues/detail?id=722

Somewhat unfortunately, this is working-as-designed.

Because of the way just-in-time-bindings work, in the HelloModulePrivate,  
Guice does not know that the statement:
  bind(HelloWord.class).to(HelloWorldImpl.class)
also means that 'HelloWorldImpl' is 'private'.  The statement is only  
saying, "Link HelloWorld to HelloWordImpl".  Because of that, HelloWordImpl  
is actually being bound in the parent module, and the interceptor in the  
private module can't see it.

This is why HelloModulePrivateNoInterface works -- you have a separate  
bind(HelloWorldImpl.class) line, telling Guice that HelloWorldImpl wants to  
be private.

If you add that bind statement (doesn't need to be a singleton as it is in  
HelloModulePrivateNoInterface) in the HelloModulePrivate, then things will  
start working.

Another fix would be to add 'binder().requireExplicitBindings()' to the  
parent Module, and that will tell Guice that you don't want just-in-time  
bindings at all, and everything should exist in the Module is was declared  
in.

Comment #4 on issue 722 by wix...@gmail.com: PrivateModule prevents  
interceptors to be applied
http://code.google.com/p/google-guice/issues/detail?id=722

A bit surprising, but both your solutions work fine for me.
Many thanks for the prompt and useful reply!