System and method for the hot deployment of shared modules, for example standalone resource adaptor modules (RARs), in systems. A class loader mechanism may utilize, in a hierarchy of class loaders, a shared "delegator" class loader which delegates received load class requests to a chain of class loaders, each representing a hot-deployable module. Hot deployment of a module results in the redeployment of the associated class loader in the chain rather than in a single, shared class loader. In one embodiment, when a load class request is received, the delegator class loader traverses the chain to find the class loader to load the class indicated by the request, the request is delegated to the class loader, and the class loader loads the class. If the module and class loader are subsequently redeployed, the redeployed version of the class loader loads the new version of the class.