Memory efficient classloading to reduce the number of class copies
View Patent ↗A system and method are disclosed for decreasing the number of duplicate library copies loaded into memory without endangering the security of applications in a runtime environment. In a preferred embodiment, applications in the runtime environment may be provided with a delegation classloader that identifies any libraries referenced by the delegation classloader's respective application. The delegation classloaders then delegate the task of providing the referenced libraries to a distinct software component. In a preferred embodiment, the distinct software component may be another delegation classloader or other loader adapted to look at a single library or a small set of libraries. These “atomic” classloaders can be freely shared by multiple applications since they do not expose any application's internals. Each atomic classloader preferably loads one copy of its associated library or libraries into memory. This single instance of shared library code is made available to multiple applications without requiring explicit cooperation between applications or endangering their security.
1. A computer-based method for reducing memory consumption by reducing identical resources in a virtual machine environment, said computer-based method implemented in computer readable program code, said computer readable program code stored in computer memory, said computer-based method comprising the steps of:
loading an application in said virtual machine environment;
a plurality of class loaders in memory, each class loader in said plurality of class loaders being associated with a library code;
a store comprising a plurality of references to existing class loaders stored in the memory,
creating a delegation class loader (DCL), wherein said DCL identifies one or more libraries referenced by said loaded application and said DCL determining if an existing class loader is available for loading at least one library among said one or more libraries stored in the memory and said DCL determining if a reference exists to said existing class loader for said at least one library;
delegating task of loading said at least one library to said existing class loader based on said determined reference; and
said delegating step limiting identical resources in memory and reducing memory consumption by not creating class loaders to load libraries that are already loaded by existing class loaders.
2. The computer-based method of claim 1 , wherein the virtual machine environment is a Java virtual machine environment.
3. A computer-based system for reducing memory consumption in a virtual machine environment by reducing copies of code in memory, comprising:
a virtual machine environment for executing code;
a plurality of class loaders in memory, each class loader in said plurality of class loaders being associated with a library code;
a store comprising a plurality of references to existing class loaders stored in the memory,
computer readable program code stored in said memory that, upon loading a new application in said virtual machine environment: creating a delegation class loader (DCL), said DCL identifying at least one library referenced by said loaded new application, determining if an existing class loader is available in said store for loading said at least one library and determining if a reference exists for said existing class loader, and delegating a task of loading said at least one library to said existing class loader based on said determined reference; and
said delegation limiting identical resources in said memory and reducing memory consumption by not creating class loaders to load libraries that are already loaded by existing class loaders.
4. A computer-based system for reducing memory consumption in a run time environment by reducing copies of code in memory, comprising:
a processor; and
computer storage storing computer readable program code that is executable by said processor to reduce memory consumption in a run time environment by reducing copies of code in memory, said computer storage comprising:
computer readable program code loading an application in said run time environment;
computer readable program code implementing a plurality of class loaders in memory, each class loader in said plurality of class loaders being associated with a library code;
computer readable program code implementing a store in memory comprising a plurality of references to existing class loaders stored in the memory,
computer readable program code creating a delegation class loader (DCL), wherein said DCL identifies one or more libraries referenced by said loaded application, said DCL determining if an existing class loader is available for loading at least one library among said one or more libraries, and said DCL determining if a reference exists to said existing class loader for said at least one library;
computer readable program code delegating task of loading said at least one library to said existing class loader based on said determined reference; and
computer readable program code limiting, based on said delegation, identical resources in memory and reducing memory consumption by not creating class loaders to load libraries that are already loaded by existing class loaders.
5. The computer-based system of claim 4 , wherein the runtime environment is a .lava runtime environment.
6. The computer-based system of claim 4 , wherein the runtime environment is a .Net runtime environment.