Question: I would like to avoid class loader leaks due to un-removed listeners. To facilitate this i believe weak or soft references to listeners would help. Strictly the only Collection methods i need are add() and iterator().

Are there any foss libraries with a Set or List that uses Weak or Soft References. 

Any suggestions would be appreciated, otherwise i will write my own.

Answer: 
Enter `http://localhost/Users/home/Documents/facebook/` as your "Site Domain" on the developer app:

<https://developers.facebook.com/apps/>{api\_key}/summary

Replace {api\_key} with yours; or find a link at <https://developers.facebook.com>

Interestingly enough, Facebook lets you type anything into the domain so it can be an offline URL (such as localhost or a local port) and Facebook will redirect to it after authentication.
You can test Facebook applications locally if you add an entry to your hosts file which points to any subdomain of the root domain you gave Facebook. For example, if your domain is example.com, you can add entry to your hosts file pointing fbtest.example.com to localhost (127.0.0.1).

You can then test away locally without having to edit your Facebook app configuration (assuming your local server is set to serve the same content to all subdomains).

Alternatively, if it's important to have the exact domain, you can just add an entry for the root domain. It just means you won't be able to access the live site while testing.