This request seems to be a request for API code to control the inner AuthCache JDK class used in some network connections. Some environments may use code like following to achieve this with JDK:

AuthCacheImpl authCacheImpl = new AuthCacheImpl();
final HashMap storage = new HashMap();
authCacheImpl.setMap(storage);
AuthCacheValue.setAuthCache(authCacheImpl);

There may be a case for this cache to be exposed similar to what developers can do with the Apache HttpClient (e.g. BasicCredentialsProvider)