Getting NPE while receiving the reply message using RabbitTemplate - spring-amqp

Question

I have two microservices. one contains the REST controller which has the Get method which receives the message when sent to specific queue. other microservice just sends the reply message to same queue so that processed message can be seen in the browser when hit the REST API
however, getting NPE while receiving the message.
below is the complete stack-trace:
2018-05-19 15:46:13.409 INFO 30104 --- [nio-8097-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/unit] : Initializing Spring FrameworkServlet 'dispatcherServlet' 2018-05-19 15:46:13.409 INFO 30104 --- [nio-8097-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started 2018-05-19 15:46:13.443 INFO 30104 --- [nio-8097-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 34 ms 2018-05-19 15:46:13.533 INFO 30104 --- [nio-8097-exec-1] o.s.a.r.c.CachingConnectionFactory : Attempting to connect to: [35.154.27.134:5672] 2018-05-19 15:46:13.593 INFO 30104 --- [nio-8097-exec-1] o.s.a.r.c.CachingConnectionFactory : Created new connection: rabbitConnectionFactory#5b2b49d6:0/SimpleConnection#3e4f13fa [delegate=amqp://guest#35.154.27.134:5672/, localPort= 58742] 2018-05-19 15:46:18.681 ERROR 30104 --- [nio-8097-exec-1] o.a.c.c.C.[.[.[.[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [/unit] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at com.infy.ci.unitamqpservice.UnitAmqpRestController.getAggregatedDataForSectionOfNightlyBuild(UnitAmqpRestController.java:83) ~[classes!/:0.0.1-SNAPSHOT]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_151]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_151]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_151]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_151]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_151]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_151]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.27.jar!/:8.5.27]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]
further, when hitting the REST API in the web browser, getting following log on the console
2018-05-19 15:45:22.328 INFO 30023 --- [ main]
o.s.j.e.a.AnnotationMBeanExporter : Located managed bean
'rabbitConnectionFactory': registering with JMX server as MBean
[org.springframework.amqp.rabbit.connection:name=rabbitConnectionFactory,type=CachingConnectionFactory]
2018-05-19 15:45:22.423 INFO 30023 --- [ main]
o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase
2147483647 2018-05-19 15:45:22.445 INFO 30023 --- [cTaskExecutor-1]
o.s.a.r.c.CachingConnectionFactory : Attempting to connect to:
[35.154.27.134:5672] 2018-05-19 15:45:22.471 INFO 30023 ---
[cTaskExecutor-1] o.s.a.r.c.CachingConnectionFactory : Created
new connection:
rabbitConnectionFactory#325fc787:0/SimpleConnection#38a7acf7
[delegate=amqp://guest#35.154.27.134:5672/, localPort= 58736]
2018-05-19 15:45:22.875 INFO 30023 --- [ main]
s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s):
8099 (http) 2018-05-19 15:45:22.902 INFO 30023 --- [ main]
com.infy.ci.unitdbamqpservice.RPCServer : Started RPCServer in 7.517
seconds (JVM running for 8.286) Sat May 19 15:45:23 UTC 2018 WARN:
Establishing SSL connection without server's identity verification is
not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+
requirements SSL connection must be established by default if explicit
option isn't set. For compliance with existing applications not using
SSL the verifyServerCertificate property is set to 'false'. You need
either to explicitly disable SSL by setting useSSL=false, or set
useSSL=true and provide truststore for server certificate
verification. Sat May 19 15:46:13 UTC 2018 WARN: Establishing SSL
connection without server's identity verification is not recommended.
According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL
connection must be established by default if explicit option isn't
set. For compliance with existing applications not using SSL the
verifyServerCertificate property is set to 'false'. You need either to
explicitly disable SSL by setting useSSL=false, or set useSSL=true and
provide truststore for server certificate verification.
can this be the reason for NPE ? i have already included following in the JDBC code but still no luck.
prop.setProperty("useSSL", "false");
prop.setProperty("autoReconnect", "true");
both the services are checked-in at github:
https://github.com/irfanjs/unitamqpservice
https://github.com/irfanjs/unitdbamqpservice

Answer 1

return rabbitTemplate.convertSendAndReceive("myExchange", requestQueueName, message).toString();
You are unconditionally calling toString() on the reply.
The reply will be null if the template's replyTimeout is exceeded before the reply is received (the timeout defaults to 5 seconds).
You must check for null result before calling toString().
just sends the reply message to same queue
You can't send the reply to the same queue - it must go to the replyTo header in the request.
If you use a #RabbitListener or MessageListenerAdapter on the server side, it will be taken care of for you.
This has nothing to do with SSL
WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set.
That warning is about MySQL.
EDIT
I just hacked your applications down to the bare minimum and they work fine for me...
#Controller
#Configuration
#PropertySource("classpath:/application.properties")
#RequestMapping("/unittestdata")
public class UnitAmqpRestController {
private final String requestQueueName = "rpc_queue1";
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
private final Logger logger = LoggerFactory.getLogger(UnitAmqpRestController.class);
private final RabbitTemplate rabbitTemplate;
#Autowired
public UnitAmqpRestController(RabbitTemplate rabbitTemplate) {
this.rabbitTemplate = rabbitTemplate;
rabbitTemplate.setReplyTimeout(15_000L);
}
#RequestMapping(value = "/{projectid}/ut/aggregate",
method = RequestMethod.GET,
produces = MediaType.TEXT_HTML_VALUE)
public #ResponseBody String getAggregatedDataForSectionOfNightlyBuild(#PathVariable("projectid") int projectid,
#RequestParam("buildtype") String buildtype, #RequestParam("build") String build) throws Exception {
if (build.toLowerCase().equals("latest") && buildtype.equals("nightly")) {
String message = String.format("aggregate");
logger.info("Sending: " + message);
Object returned = rabbitTemplate.convertSendAndReceive("", requestQueueName, message);
logger.info("Reply: " + returned);
if (returned == null) {
throw new RuntimeException("failed to get a response");
}
return returned.toString();
}
else {
return null;
}
}
}
and
#Configuration
#SpringBootApplication
#PropertySource("classpath:/application.properties")
public class RPCServer {
private static final Logger logger = LoggerFactory.getLogger(RPCServer.class);
public static void main(String[] args) throws IOException, TimeoutException, InterruptedException {
SpringApplication.run(RPCServer.class, args);
}
private static final String RPC_QUEUE_NAME = "rpc_queue1";
#Bean
public Queue queue() {
return new Queue(RPC_QUEUE_NAME);
}
#Component
public static class RpcListener {
#RabbitListener(queues = RPC_QUEUE_NAME)
public String reply(String request) throws IOException, TimeoutException, ClassNotFoundException, SQLException {
logger.info(request);
return request.toUpperCase();
}
}
}
and
2018-05-20 12:46:00.298 INFO 13369 --- [nio-8097-exec-1] c.i.c.u.UnitAmqpRestController : Sending: aggregate
...
o.s.amqp.rabbit.core.RabbitTemplate : Publishing message on exchange [], routingKey = [rpc_queue1]
2018-05-20 12:46:00.554 DEBUG 13369 --- [nio-8097-exec-1] o.s.amqp.rabbit.core.RabbitTemplate : Reply: (Body:'AGGREGATE' MessageProperties [headers={}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=, receivedRoutingKey=amq.rabbitmq.reply-to.g2dkABByYWJiaXRAbG9jYWxob3N0AAAHFAAAAAAC.3M1LyvOdR9dHQehSV4l67A==, receivedDelay=null, deliveryTag=1, messageCount=null, consumerTag=null, consumerQueue=null])
2018-05-20 12:46:00.561 INFO 13369 --- [nio-8097-exec-1] c.i.c.u.UnitAmqpRestController : Reply: AGGREGATE