Abstract: A computer system has one or more program classes loaded in it. Each class includes a constant pool which is used for storing data items related to the program class. At least some of these data items need to undergo a resolution before they can be used, which transforms them from their initially loaded value into a usable value. In accordance with the invention, the system maintains both the unresolved value and the resolved value in the constant pool entry for a resolved data item. This allows the resolution process to be performed without using locks, thereby avoiding potential system delays due to contention for locks.

Abstract: A computer system includes multiple class loaders for loading program class files into the system. A constraint checking mechanism is provided wherein a first class file loaded by a first class loader makes a symbolic reference to a second class file loaded by a second class loader, the symbolic reference including a descriptor of a third class file. The constraint mechanism requires that the first and second class files agree on the identity of the third class file and stores a list of constraints as a set of asymmetric relationships between class loaders. Each stored constraint, for a class loader which loaded a class file that contains a symbolic reference to another class file, includes a first parameter denoting the class loader which loaded the class file to which the symbolic references is made; and a second parameter denoting a class file which is identified by a descriptor in said symbolic reference.

Abstract: A computer system has one or more program classes loaded in it. Each class includes a constant pool which is used for storing data items related to the program class. At least some of these data items need to undergo a resolution before they can be used, which transforms them from their initially loaded value into a usable value. In accordance with the invention, the system maintains both the unresolved value and the resolved value in the constant pool entry for a resolved data item. This allows the resolution process to be performed without using locks, thereby avoiding potential system delays due to contention for locks.

Abstract: An object-oriented computer system includes two or more class loaders for loading program class files into the system. A constraint checking mechanism is provided so that where a first class file loaded by a first class loader makes a symbolic reference to a second class file loaded by a second class loader, with said symbolic reference including a descriptor of a third class file, the constraint enforces that the first and second class files agree on the identity of the third class file. The constraint checking mechanism stores a list of constraints as a set of asymmetric relationships between class loaders. Each stored constraint, for a class loader which loaded a class file that contains a symbolic reference to another class file, includes a first parameter denoting the class loader which loaded the class file to which the symbolic references is made; and a second parameter denoting a class file which is identified by a descriptor in said symbolic reference.

Abstract: A host computer provides an object stored in the host computer to a target computer. In response to a need for an object at the target computer, the host computer generates and transfers to the target computer a proxy program instead of the object. The proxy program, when executed at the target computer, provides the object. Usually, the proxy program is much shorter than the object itself, and this reduces message traffic. The proxy program has various forms such as a call to another program resident in the target computer to recreate the object or a request to a function within the target computer to provide the object. The host computer can also be programmed into an object oriented environment, the object referencing other objects, and the proxy program forming an agent in the target computer which requests these other objects from the host computer only as needed by the target computer.