Tomcat – WebSocket not Working on Apache Tomcat 7 on AWS ElasticBeanstalk

I just set up me web app on top of ElasticBeanstalk. Everything seemed to work fine, until I discovered that my instance couldn't use WebSocket, every time I tried to connect internal server error code was retured.

When I checked the logs, I found NullPointerException which is highly unlikely caused by me.
Here's stacktrace:

Aug 27, 2013 5:01:18 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [WebSocketChannel] in context with path [] threw exception
java.lang.NullPointerException
    at org.apache.catalina.websocket.WebSocketServlet.getWebSocketAccept(WebSocketServlet.java:171)
    at org.apache.catalina.websocket.WebSocketServlet.doGet(WebSocketServlet.java:116)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:680)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:679)

My instance is running version 7.0.27. When I checked the source code of tomcat to see the source of problem I couldn't understand a thing.

Any ideas what seems to be causing the problem? Does WebSockets not work with ElasticBeanstalk and Apache Tomcat?