Rich Internet applications (RIAs) can use the Java Network Launch Protocol (JNLP) API to perform extensive operations on the user's environment. When launched by using JNLP, even unsigned RIAs can perform the following operations with the user's permission:
FileSaveServiceAPI to access the user's file system..
ClipboardServiceAPI to access the shared system-wide clipboard.
PrintServiceAPI to access printing functions.
PersistenceServiceAPI to access persistence storage.
DownloadServiceAPI to control how the RIA is downloaded and cached.
DownloadServiceListenerAPI to determine progress of the RIA's download.
SingleInstanceServiceAPI to decide how to handle arguments when multiple instances of the RIA are launched.
ExtendedServiceAPI to request permission to open certain files that have not been opened before.
Check the JNLP API documentation to see the complete list of the functionality available to RIAs that are launched by using JNLP.