# Package javax.servlet

The javax.servlet package contains a number of classes and interfaces that describe and define the contracts between a servlet class and the runtime environment provided for an instance of such a class by a conforming servlet container.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  AsyncContext | Class representing the execution context for an asynchronous operation that was initiated on a ServletRequest.
  AsyncListener | Listener that will be notified in the event that an asynchronous operation initiated on a ServletRequest to which the listener had been added has completed, timed out, or resulted in an error.
  Filter | A filter is an object that performs filtering tasks on either the request to a resource (a servlet or static content), or on the response from a resource, or both.
  FilterChain | A FilterChain is an object provided by the servlet container to the developer giving a view into the invocation chain of a filtered request for a resource.
  FilterConfig | A filter configuration object used by a servlet container to pass information to a filter during initialization.
  FilterRegistration | Interface through which a `Filter` may be further configured.
  FilterRegistration.Dynamic | Interface through which a `Filter` registered via one of the `addFilter` methods on `ServletContext` may be further configured.
  ReadListener | This class represents a call-back mechanism that will notify implementations as HTTP request data becomes available to be read without blocking.
  Registration | Interface through which a `Servlet` or `Filter` may be further configured.
  Registration.Dynamic | Interface through which a `Servlet` or `Filter` registered via one of the `addServlet` or `addFilter` methods, respectively, on `ServletContext` may be further configured.
  RequestDispatcher | Defines an object that receives requests from the client and sends them to any resource (such as a servlet, HTML file, or JSP file) on the server.
  Servlet | Defines methods that all servlets must implement.
  ServletConfig | A servlet configuration object used by a servlet container to pass information to a servlet during initialization.
  ServletContainerInitializer | Interface which allows a library/runtime to be notified of a web application's startup phase and perform any required programmatic registration of servlets, filters, and listeners in response to it.
  ServletContext | Defines a set of methods that a servlet uses to communicate with its servlet container, for example, to get the MIME type of a file, dispatch requests, or write to a log file.
  ServletContextAttributeListener | Interface for receiving notification events about ServletContext attribute changes.
  ServletContextListener | Interface for receiving notification events about ServletContext lifecycle changes.
  ServletRegistration | Interface through which a `Servlet` may be further configured.
  ServletRegistration.Dynamic | Interface through which a `Servlet` registered via one of the `addServlet` methods on `ServletContext` may be further configured.
  ServletRequest | Defines an object to provide client request information to a servlet.
  ServletRequestAttributeListener | Interface for receiving notification events about ServletRequest attribute changes.
  ServletRequestListener | Interface for receiving notification events about requests coming into and going out of scope of a web application.
  ServletResponse | Defines an object to assist a servlet in sending a response to the client.
  SessionCookieConfig | Class that may be used to configure various properties of cookies used for session tracking purposes.
  SingleThreadModel | Deprecated As of Java Servlet API 2.4, with no direct replacement.
  WriteListener | Callback notification mechanism that signals to the developer it's possible to write content without blocking.

- Class Summary
  Class | Description
  --- | ---
  AsyncEvent | Event that gets fired when the asynchronous operation initiated on a ServletRequest (via a call to `ServletRequest.startAsync()` or `ServletRequest.startAsync(ServletRequest, ServletResponse)`) has completed, timed out, or produced an error.
  GenericServlet | Defines a generic, protocol-independent servlet.
  HttpConstraintElement | Java Class representation of an `HttpConstraint` annotation value.
  HttpMethodConstraintElement | Java Class represntation of an `HttpMethodConstraint` annotation value.
  MultipartConfigElement | Java Class represntation of an `MultipartConfig` annotation value.
  ServletContextAttributeEvent | Event class for notifications about changes to the attributes of the ServletContext of a web application.
  ServletContextEvent | This is the event class for notifications about changes to the servlet context of a web application.
  ServletInputStream | Provides an input stream for reading binary data from a client request, including an efficient `readLine` method for reading data one line at a time.
  ServletOutputStream | Provides an output stream for sending binary data to the client.
  ServletRequestAttributeEvent | This is the event class for notifications of changes to the attributes of the servlet request in an application.
  ServletRequestEvent | Events of this kind indicate lifecycle events for a ServletRequest.
  ServletRequestWrapper | Provides a convenient implementation of the ServletRequest interface that can be subclassed by developers wishing to adapt the request to a Servlet.
  ServletResponseWrapper | Provides a convenient implementation of the ServletResponse interface that can be subclassed by developers wishing to adapt the response from a Servlet.
  ServletSecurityElement | Java Class represntation of a `ServletSecurity` annotation value.

- Enum Summary
  Enum | Description
  --- | ---
  DispatcherType | Enumeration of filter dispatcher types.
  SessionTrackingMode | Enumeration of session tracking modes.

- Exception Summary
  Exception | Description
  --- | ---
  ServletException | Defines a general exception a servlet can throw when it encounters difficulty.
  UnavailableException | Defines an exception that a servlet or filter throws to indicate that it is permanently or temporarily unavailable.

## Package javax.servlet Description

The javax.servlet package contains a number of classes and interfaces that describe and define the contracts between a servlet class and the runtime environment provided for an instance of such a class by a conforming servlet container.

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