Problem with Groups (editing)

Version:  Openfire 3.9.1

Version und Anbieter der JVM:   1.8.0 Oracle Corporation -- Java HotSpot(TM) Embedded Client VM

User/Groups > Groups > Edit

HTTP ERROR 500

Problem accessing /group-edit.jsp. Reason:

    org.jivesoftware.openfire.group.Group.getProperties()Ljava/util/Map;

Caused by:

java.lang.NoSuchMethodError: org.jivesoftware.openfire.group.Group.getProperties()Ljava/util/Map;

    at org.jivesoftware.openfire.admin.group_002dedit_jsp._jspService(group_002dedit_j sp.java:306)

    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)

    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:547)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1359)

    at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:11 8)

    at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1330)

    at org.jivesoftware.util.LocaleFilter.doFilter(LocaleFilter.java:74)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1330)

    at org.jivesoftware.util.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingF ilter.java:50)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1330)

    at org.jivesoftware.admin.PluginFilter.doFilter(PluginFilter.java:78)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1330)

    at org.jivesoftware.admin.AuthCheckFilter.doFilter(AuthCheckFilter.java:164)

    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.ja va:1330)

    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:478)

    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)

    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:520)

    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:22 7)

    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:94 1)

    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:409)

    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186 )

    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:875 )

    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)

    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandler Collection.java:250)

    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.jav a:149)

    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)

    at org.eclipse.jetty.server.Server.handle(Server.java:349)

    at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:441)

    at org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConne ction.java:919)

    at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:582)

    at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:218)

    at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:51 )

    at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.jav a:586)

    at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java :44)

    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:598 )

    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:533)

    at java.lang.Thread.run(Thread.java:744)