The Helper Application checks to see if it has already downloaded the class from this server. If it has not, it requests the Java byte-code of the class. The distributable class is written by the developer to contain all of the application-specific implementations of the job distribution. The class must inherit from the class Distributable , which was developed as part of this project, and must have methods getArgs , run , and sendResults as described below. The resulting data transmission is handled by the programmer.
Execution is done by calling the object s run method.
The programmer s run method can operate on the data in any way permitted. Because users would not want their computers executing foreign code without prior knowledge of its functionality, we created a security policy that closely resembles the applet security policy. The only difference is that an applet has certain rights on documents and classes contained in the same or related URL that the applet was loaded from. But, because a downloaded class is not referenced by a URL, the class does not get the same rights as an applet does. A downloaded class s network ability is restricted to connecting only to the host it came from.