Patent ID: 6851111

Claim:
An object-oriented computer system, including: two or more class loaders for loading program class files into the system; and a constraint checking mechanism 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, 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; said constraint checking mechanism including means for; creating a first constraint data structure in an internal cache associated with said first class loader and a second constraint data structure in an internal cache associated with said second class loader; and recording a constraint, in said first constraint data structure associated with said first class loader, as an asymmetric relationship between said first and said second class loaders; wherein said first constraint data structure associated with said first class loader comprises; a first parameter denoting said third class file, which is identified by said descriptor in said symbolic reference; and a second parameter denoting said second class loader, which loaded said third class file.