Abstract: A unique class loader called the Firewall Class Loader is described wherein the firewall class loader either uses positive filters or a combination of positive and negative filters. Negative filters provide for a list of classes that a class loader will not pass load requests to its parent in the class loader hierarchy. On the other hand, positive filters provide for a list of classes that a class will pass load requests to its parent in the class loader hierarchy, and all other requests would be filtered out. Variations and combinations of Firewall Class Loaders enable specialized configurations to increase speed and ensure that each vendor's applications work correctly in all user deployments.