Abstract: Location-independent references include a live reference containing a location of a remote object and a universally unique identifier (UUID) which provides a unique global reference to that remote object. If a method call to the remote object using the live reference fails, the UUID is used to obtain a new reference to the remote object and the new reference is then used to make another method call. A new reference can be obtained from an identifier directory that contains a mapping between UUIDs and location-independent references. When a remote object is first created, or when a remote object is moved from one location to another, the remote object registers with any and all such directories that it can find in its environment. These registrations are leased; that is, if they are not occasionally refreshed by the remote object which registered them, they are dropped from the directory.

Abstract: A distributed database system includes a central data server, and a plurality of application nodes for receiving connections from clients. Each application node is in communication with the central data server, and has a data cache which maintains local copies of recently used data items. The central data server keeps track of which data items are stored in each data cache and makes callback requests to the data caches to request the return of data items that are needed elsewhere. Data items, including modified data items, are cached locally at a local application node so long as the locally cached data items are only being accessed by the local application node. The local application node handles transactions and stores changes to the data items. The local application node forwards changes, in order by transaction, to the central data server to insure consistency, thereby providing limited durability write caching.

Abstract: A method for using dependency-based grouping to establish class identity comprises categorizing a plurality of classes into a set of class groups based at least in part on one or more dependencies between the classes, and generating metadata to be use for loading the classes, where the metadata includes a mapping between the set of class groups and the plurality of classes. The metadata may also include respective signatures for class groups and/or the individual classes. The method may also include validating, using at least a portion of the metadata, the identity of a particular version of a class of the plurality of classes, prior to loading the version for execution.

Abstract: Systems and methods for securing the content integrity of and access to object data and code in a distributed system. Content protecting URLs provide a mechanism for checking code or data transmitted out-of-band. Dynamic permission grants are supported during program execution for code or users unknown prior to runtime.

Abstract: Systems and methods for securing the content integrity of and access to object data and code in a distributed system. Content protecting URLs provide a mechanism for checking code or data transmitted out-of-band. Dynamic permission grants are supported during program execution for code or users unknown prior to runtime.