1. A system for proxy data source support in a multitenant application server environment, comprising: one or more computers, including an application server environment executing thereon, together with a plurality of deployable resources which can be used within the application server environment, one or more resource group templates, which define groupings of deployable resources within a domain, and one or more partitions, wherein each partition provides an administrative and runtime subdivision of the domain, that can be associated with a tenant; and a proxy data source, the proxy data source enabling an application running within the application server environment to access a first of a plurality of data sources, the proxy data source comprising a JNDI name that is not tenant specific; wherein the proxy data source uses a caller context to enable the application running within the application server environment to access the first of the plurality of data sources.