javax.jnlp.DownloadService2 was added to 6u18 to provide advanced JNLP cache management. Customers would consider it useful to have information about the
size of cached resources. We should probably add getSize() to DownloadService2.ResourceSpec.
I am adding getSize() and implementation to the API.
As per request from customer contact, I will also add getExpirationDate() and getLastModified() to ResourceSpec.