1. A method of operating a data processing system to examine a compiled program for violations of a set of rules that do not constitute violations detected by a compiler used to compile the compiled program, said method comprising: obtaining a restricted rule set defined in terms of rules in a decompiled representation of said program, said restricted rule set prohibiting language commands that would otherwise be allowed by said compiler in a subset of classes in said compiled program while allowing said language commands in another class of said program; decompiling said compiled program to said decompiled representation of said compiled program in which said restricted rule set is defined; examining said decompiled representation of said compiled program for a violation of said restricted rule set to determine if any of said rules are violated; and providing an output indicating that one of said rules was violated, wherein said restricted rule set only applies to a portion of said compiled program and wherein decompiling said compiled program comprises decompiling said portion of said compiled program while not decompiling another portion of said compiled program, said portion of said compiled program comprising a set of sub-classes of a class, and wherein decompiling said program comprises identifying a location in said compiled program of instructions pertaining to said set of sub-classes, said data processing system generating a certificate if said compiled program does not violate said restricted rule set.
6. The method of claim 1 wherein said certificate is readable by a runtime system that runs said compiled program.