1. A system for supporting web services in a multitenant application server environment, comprising: one or more computers, each including a microprocessor; an application server environment, executing on the one or more computers, that includes a plurality of partitions, wherein each partition includes one or more services; a web service security manager that attaches security policies to the one or more web services in each partition; wherein the web service security manager intercepts a request targeted to a web service in a particular partition and executes one or more security policies attached to the web service on the request, to determine whether to deliver the request to the targeted web service.