i am using Callable to apply multi threading with SOAP requests. It was working before, but suddenly it stop working and it is giving me a nullPointer Exception. Below part of my code:
public List<ServiceResponse> soapTransaction(String folderName, SoapVariables soapVariables){
List<String> allMonitorIds = this.getMonitorIds(folderName);
List<Callable<ServiceResponse>> list = new ArrayList<>();
List<ServiceResponse> responses = new ArrayList<>();
int counter = 0;
for(int j = 0; j < Math.ceil(allMonitorIds.size() / 3.0); j++ ) {
int threadNumbers = ((allMonitorIds.size() - (j*3)) < 3) ? (allMonitorIds.size() - (j*3)) : 3 ;
ExecutorService executorService = Executors.newFixedThreadPool(threadNumbers);
for (int i = counter; i < threadNumbers+counter; i++) {
list.add(new MainRunnable(soapVariables, allMonitorIds.get(i)));
}
counter += threadNumbers;
try {
List<Future<ServiceResponse>> tasks = executorService.invokeAll(list);
for (Future<ServiceResponse> task : tasks) {
responses.add(task.get());
}
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
list.clear();
}
return responses;
}
When I debug, everything gets done until the line
List<Future<ServiceResponse>> tasks = executorService.invokeAll(list);
Where it was getting the values of "list" into into the Future. It just stop doing it??
EDIT: here is the stack trace
> java.util.concurrent.ExecutionException:
> java.lang.NullPointerException at
> java.util.concurrent.FutureTask.report(FutureTask.java:122) at
> java.util.concurrent.FutureTask.get(FutureTask.java:192) at
> HelperMethods.MainMethods.soapTransaction(MainMethods.java:35) at
> TorchWebApp.MainController.nationalPage(MainController.java:58) 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:497) at
> org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
> at
> org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
> at
> org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
> at
> org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
> at
> org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
> at
> org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
> at
> org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
> at
> org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
> at
> org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
> at
> org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) at
> org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
> at
> org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:87)
> at
> org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
> at
> org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
> at
> org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
> at
> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
> at
> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
> at
> org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
> at
> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
> at
> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
> at
> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:521)
> at
> org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
> at
> org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
> at
> org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
> at
> org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at
> org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
> at java.lang.Thread.run(Thread.java:745) Caused by:
> java.lang.NullPointerException at
> HelperMethods.MainRunnable.call(MainRunnable.java:36) at
> HelperMethods.MainRunnable.call(MainRunnable.java:10) at
> java.util.concurrent.FutureTask.run(FutureTask.java:266) at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> ... 1 more
