JON: Server becomes unavailable due to OutOfMemoryError: Java heap space when multiple users are accessing the web UI

ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/jboss-remoting-servlet-invoker].[ServerInvokerServlet]] Servlet.service() for servlet ServerInvokerServlet threw exception
javax.management.RuntimeErrorException
     at org.jboss.mx.interceptor.ReflectedDispatcher.handleInvocationExceptions(ReflectedDispatcher.java:178)
     at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:163)
     at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
     at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
     at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
     at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
     at javax.management.MBeanServerInvocationHandler.invoke(MBeanServerInvocationHandler.java:201)
     at $Proxy381.processRequest(Unknown Source)
     at org.jboss.remoting.transport.servlet.web.ServerInvokerServlet.processRequest(ServerInvokerServlet.java:128)
     at org.jboss.remoting.transport.servlet.web.ServerInvokerServlet.doPost(ServerInvokerServlet.java:157)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.rhq.helpers.rtfilter.filter.RtFilter.doFilter(RtFilter.java:124)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
     at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
     at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
     at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
     at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446)
     at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.OutOfMemoryError: Java heap space