[DLC] If the queue doesn't exist when restoring messages from the DLC an error is thrown

[Drifftr]

Steps to reprodiuce

1. Add some messages to the DLC.
2. Now delete the relevent queue.
3. Try to restore the messages.

Issue : Following error is thrown.

 ERROR {org.apache.axis2.rpc.receivers.RPCMessageReceiver} -  java.lang.NullPointerException
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.apache.axis2.rpc.receivers.RPCUtil.invokeServiceClass(RPCUtil.java:212)
	at org.apache.axis2.rpc.receivers.RPCMessageReceiver.invokeBusinessLogic(RPCMessageReceiver.java:117)
	at org.apache.axis2.receivers.AbstractInOutMessageReceiver.invokeBusinessLogic(AbstractInOutMessageReceiver.java:40)
	at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:110)
	at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
	at org.apache.axis2.transport.local.LocalTransportReceiver.processMessage(LocalTransportReceiver.java:169)
	at org.apache.axis2.transport.local.LocalTransportReceiver.processMessage(LocalTransportReceiver.java:82)
	at org.wso2.carbon.core.transports.local.CarbonLocalTransportSender.finalizeSendWithToAddress(CarbonLocalTransportSender.java:45)
	at org.apache.axis2.transport.local.LocalTransportSender.invoke(LocalTransportSender.java:77)
	at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:442)
	at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:430)
	at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:225)
	at org.apache.axis2.client.OperationClient.execute(OperationClient.java:149)
	at org.wso2.carbon.andes.stub.AndesAdminServiceStub.restoreMessagesFromDeadLetterQueue(AndesAdminServiceStub.java:783)
	at org.apache.jsp.queues.dlc_005fmessage_005frestore_005fajaxprocessor_jsp._jspService(dlc_005fmessage_005frestore_005fajaxprocessor_jsp.java:81)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.wso2.carbon.ui.JspServlet.service(JspServlet.java:155)
	at org.wso2.carbon.ui.TilesJspServlet.service(TilesJspServlet.java:80)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.eclipse.equinox.http.helper.ContextPathServletAdaptor.service(ContextPathServletAdaptor.java:37)
	at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
	at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)
	at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.wso2.carbon.tomcat.ext.filter.CharacterSetFilter.doFilter(CharacterSetFilter.java:61)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:99)
	at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:49)
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:62)
	at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:159)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
	at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:57)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1739)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1698)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)
Caused by: javax.management.RuntimeMBeanException: java.lang.NullPointerException
	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrow(DefaultMBeanServerInterceptor.java:839)
	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrowMaybeMBeanException(DefaultMBeanServerInterceptor.java:852)
	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:821)
	at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
	at org.wso2.carbon.andes.core.internal.registry.QueueManagementBeans.restoreMessagesFromDeadLetterQueue(QueueManagementBeans.java:246)
	at org.wso2.carbon.andes.core.QueueManagerServiceImpl.restoreMessagesFromDeadLetterQueue(QueueManagerServiceImpl.java:237)
	at org.wso2.carbon.andes.admin.AndesAdminService.restoreMessagesFromDeadLetterQueue(AndesAdminService.java:175)
	... 63 more
Caused by: java.lang.NullPointerException
	at org.wso2.andes.server.information.management.QueueManagementInformationMBean.restoreMessagesFromDeadLetterQueue(QueueManagementInformationMBean.java:331)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
	at sun.reflect.GeneratedMethodAccessor41.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
	at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:112)
	at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:46)
	at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:237)
	at com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)
	at com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:252)
	at javax.management.StandardMBean.invoke(StandardMBean.java:405)
	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
	... 67 more

With reference to : https://wso2.org/jira/browse/MB-1355