StackOverflowError if you try to add GuiceFilter

_From [rkapsi](https://code.google.com/u/116755208212771764698/) on February 14, 2012 15:57:07_

I was extending a Servlet Filter from GuiceFilter (by accident) and ended up in a StackOverflowError that didn't really explain what's wrong. It took me a bit to see that I'm extending from GuiceFilter.

filter("/*").through(GuiceFilter.class);

java.lang.StackOverflowError
        at com.google.inject.Key.equals(Key.java:181)
        at java.util.HashMap.getEntry(HashMap.java:349)
        at java.util.LinkedHashMap.get(LinkedHashMap.java:280)
        at java.util.Collections$UnmodifiableMap.get(Collections.java:1282)
        at com.google.inject.internal.InheritingState.getExplicitBinding(InheritingState.java:67)
        at com.google.inject.internal.InjectorImpl.getBindingOrThrow(InjectorImpl.java:199)
        at com.google.inject.internal.InjectorImpl.getInternalFactory(InjectorImpl.java:853)
        at com.google.inject.internal.InjectorImpl.getProviderOrThrow(InjectorImpl.java:967)
        at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:1000)
        at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1009)
        at com.google.inject.servlet.FilterDefinition.init(FilterDefinition.java:104)
        at com.google.inject.servlet.ManagedFilterPipeline.initPipeline(ManagedFilterPipeline.java:98)
        at com.google.inject.servlet.GuiceFilter.init(GuiceFilter.java:172)
        at com.google.inject.servlet.FilterDefinition.init(FilterDefinition.java:114)
        at com.google.inject.servlet.ManagedFilterPipeline.initPipeline(ManagedFilterPipeline.java:98)
        at com.google.inject.servlet.GuiceFilter.init(GuiceFilter.java:172)
        at com.google.inject.servlet.FilterDefinition.init(FilterDefinition.java:114)
        at com.google.inject.servlet.ManagedFilterPipeline.initPipeline(ManagedFilterPipeline.java:98)

_Original issue: http://code.google.com/p/google-guice/issues/detail?id=685_