title: Spring Boot enable <async-supported> like in web.xml
body: <p>I have a problem with Spring Boot configuration. I got exception on some mobile devices which should use sockets:</p>
  
  <pre><code>java.lang.IllegalArgumentException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "&lt;async-supported&gt;true&lt;/async-supported&gt;" to servlet and filter declarations in web.xml. Also you must use a Servlet 3.0+ container
      at org.springframework.util.Assert.isTrue(Assert.java:65)
      at org.springframework.http.server.ServletServerHttpAsyncRequestControl.&lt;init&gt;(ServletServerHttpAsyncRequestControl.java:59)
      at org.springframework.http.server.ServletServerHttpRequest.getAsyncRequestControl(ServletServerHttpRequest.java:202)
      at org.springframework.web.socket.sockjs.transport.session.AbstractHttpSockJsSession.handleInitialRequest(AbstractHttpSockJsSession.java:202)
      at org.springframework.web.socket.sockjs.transport.handler.AbstractHttpSendingTransportHandler.handleRequestInternal(AbstractHttpSendingTransportHandler.java:66)
      at org.springframework.web.socket.sockjs.transport.handler.AbstractHttpSendingTransportHandler.handleRequest(AbstractHttpSendingTransportHandler.java:58)
      at org.springframework.web.socket.sockjs.transport.TransportHandlingSockJsService.handleTransportRequest(TransportHandlingSockJsService.java:254)
      at org.springframework.web.socket.sockjs.support.AbstractSockJsService.handleRequest(AbstractSockJsService.java:322)
      at org.springframework.web.socket.sockjs.support.SockJsHttpRequestHandler.handleRequest(SockJsHttpRequestHandler.java:88)
      at org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter.handle(HttpRequestHandlerAdapter.java:51)
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
      at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
      ...
  </code></pre>
  
  <p>As I see from the exception, I have to enable async processing by adding true into the web.xml file. But this is the problem because I don't have it - our project uses Spring Boot. </p>
  
  <p>Is there any way to provide the same functionality in Spring Boot like  does?</p>