@Provides
    public List<AuthenticationProvider> getAuthenticationProviders() {
        return Collections.unmodifiableList(boundAuthenticationProviders);
    }
Returns a list of all currently-bound AuthenticationProvider instances.

@return
    A List of all currently-bound AuthenticationProvider. The List is
    not modifiable.
guacamole/src/main/java/org/apache/guacamole/extension/ExtensionModule.java