FieldVisibilityManager This is an interface for the old FieldVisibilityBean. 
HttpServletVariables This component can provide the variables that a typical javax.servlet.http.HttpServlet would receive. 
Renderable Some renderable content that can be rendered by a render tag. 
RequestParameterKeys Stores a number of constants used to reference keys in the HttpServletRequest. 
ServletContextKeys Provides constants for referencing objects in the servlet context in JIRA. 
SessionKeys Keys and constants used (usually) to store objects in scopes (request / session etc)  


CookieNames Names of HTTP cookies. 
ExecutingHttpRequest This has a thread local that contains the currently executing javax.servlet.http.HttpServletRequest

It is set in the entry filter and set back to null at the end of the filter chain 

HttpRequestLocal<T> Per-request variable (similar to ThreadLocal, but request-scoped). 
HttpServletVariablesImpl An injectable alternative to ExecutingHttpRequest 
JiraMultipartRequestWrapper Wrapper class so that we can parse and replace special characters in the request params. 
ServletContextProvider A means to acquire the ServletContext. 
ServletContextProviderListener The listener implementation to acquire and hold the ServletContext.