GWT 2.7 exception when launching in dev mode from

I am trying to run my GWT 2.7 application in dev mode from Eclipse (Kepler). When I launch it I get the following exception. Can someone tell me what I can do to fix this?

Starting Jetty on port 8888 [WARN] FAILED org.eclipse.jetty.security.ConstraintSecurityHandler@6c86fa3c: java.lang.ArrayStoreException: org.eclipse.jetty.security.SecurityHandler$1 java.lang.ArrayStoreException: org.eclipse.jetty.security.SecurityHandler$1 at org.eclipse.jetty.util.LazyList.addToArray(LazyList.java:455) at org.eclipse.jetty.server.handler.ContextHandler.addEventListener(ContextHandler.java:599) at org.eclipse.jetty.security.SecurityHandler.doStart(SecurityHandler.java:300) at org.eclipse.jetty.security.ConstraintSecurityHandler.doStart(ConstraintSecurityHandler.java:453) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95) at org.eclipse.jetty.server.handler.ScopedHandler.doStart(ScopedHandler.java:115) at org.eclipse.jetty.server.session.SessionHandler.doStart(SessionHandler.java:124) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95) at org.eclipse.jetty.server.handler.ScopedHandler.doStart(ScopedHandler.java:115) at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:763) at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:249) at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1242) at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:717) at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:494) at com.google.gwt.dev.shell.jetty.JettyLauncher$WebAppContextWithReload.doStart(JettyLauncher.java:541) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95) at org.eclipse.jetty.server.handler.RequestLogHandler.doStart(RequestLogHandler.java:162) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95) at org.eclipse.jetty.server.Server.doStart(Server.java:282) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:740) at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:632) at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1054) at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:836) at com.google.gwt.dev.DevMode.main(DevMode.java:413)

Are you running it with the -nosuperDevMode flag?

GWT stopped supporting regular Dev Mode. The Browser's themselves (Chrome for sure) no longer support the API that enabled Dev Mode. You probably want to look at Super Dev Mode, which is the currently supported method. You can debug in the browser with it