8. A system comprising: a storage device for storing: a class definition in a single language computing environment, wherein: the single language computing environment has a native object system, the class definition is used to instantiate a plurality of objects from a plurality of classes, the plurality of object are accessible in the single language computing environment, the plurality of classes are defined in a plurality of different types of foreign object systems, the foreign object systems comprise a first foreign object system, and the first foreign object system is hosted in a virtual machine; a processor for executing instructions for: implementing a mapping facility in the single language computing environment, bidirectionally mapping foreign metadata to single language computing environment metadata, wherein: the foreign metadata is associated with foreign objects created with the plurality of different types of foreign object systems, the single language computing environment metadata is created in a form supported by the single language computing environment, and the single language computing environment metadata is usable by the plurality of objects instantiated from the class definition, examining the first foreign class metadata, wherein the first foreign class metadata: is metadata for a first foreign class, is created in the first foreign object system, and describes how to access an instance of the foreign object system, creating new first foreign class metadata, the new first foreign class metadata: corresponding to the first foreign class metadata, and created in a form supported by the single language computing environment, and instantiating a first object instance, the first object instance: instantiated using the class definition, and referencing the new first foreign class metadata and the instance of the foreign class.
8. A system comprising: a storage device for storing: a class definition in a single language computing environment, wherein: the single language computing environment has a native object system, the class definition is used to instantiate a plurality of objects from a plurality of classes, the plurality of object are accessible in the single language computing environment, the plurality of classes are defined in a plurality of different types of foreign object systems, the foreign object systems comprise a first foreign object system, and the first foreign object system is hosted in a virtual machine; a processor for executing instructions for: implementing a mapping facility in the single language computing environment, bidirectionally mapping foreign metadata to single language computing environment metadata, wherein: the foreign metadata is associated with foreign objects created with the plurality of different types of foreign object systems, the single language computing environment metadata is created in a form supported by the single language computing environment, and the single language computing environment metadata is usable by the plurality of objects instantiated from the class definition, examining the first foreign class metadata, wherein the first foreign class metadata: is metadata for a first foreign class, is created in the first foreign object system, and describes how to access an instance of the foreign object system, creating new first foreign class metadata, the new first foreign class metadata: corresponding to the first foreign class metadata, and created in a form supported by the single language computing environment, and instantiating a first object instance, the first object instance: instantiated using the class definition, and referencing the new first foreign class metadata and the instance of the foreign class. 13. The system of claim 8 , further comprising: a plurality of virtual machines loaded in the single language computing environment, each virtual machine hosting a different foreign object system.