java - NullpointerException while accessing Spring Bean factory + tomcat 8 startup -

we migrated java 7 java 8 , tomcat 6 tomcat 8. before migration , getting below issue during deployment of our services , deployment fails , tomcat not start.

what crazy that, not happen , intermittent (occurs once in 3 or 4 deployments).

below stack trace see during deployment.

caused by: java.lang.nullpointerexception     @ com.async.classb.createclassc(classb.java)     @ com.async.classa.afterpropertiesset(classa.java)     @ org.springframework.beans.factory.support.abstractautowirecapablebeanfactory.invokeinitmethods(abstractautowirecapablebeanfactory.java:1573)     @ org.springframework.beans.factory.support.abstractautowirecapablebeanfactory.initializebean(abstractautowirecapablebeanfactory.java:1511) 

existing code: in our code have singleton classa, injected singleton classb. , prototype classc used in classb.

in classa, have afterpropertiesset(), where-in getting instance of classb using applicationcontext.

in classb trying instance of classc using beanfactory.

exact code looks this.

public classa implements applicationcontextaware, initializingbean {       private applicationcontext applicationcontext;       public void afterpropertiesset() throws exception {         classb classb =              (classb)applicationcontext.getbean("classb");                registry.registerasynclistener(this);      }       public void setapplicationcontext(applicationcontext applicationcontext) throws beansexception {         this.applicationcontext = applicationcontext;      } }  public classb  implements lifecycle, disposablebean, beanfactoryaware {      private asyncmessagelistener createclassc(classa classa) {         logger.warn("bean factory value ... " + getbeanfactory());               classc classc = (classc) getbeanfactory().getbean("classc", classc.class);                 return classc;     }      public void setbeanfactory(beanfactory beanfactory) throws beansexception {         this.beanfactory = beanfactory;     }      public start(){ // code     }      public stop(){ // code     }      public isrunning(){ // code     }      public destroy(){ // code     }  } 

when added more loggers, saw beanfactory ggets null value intermittently , hence nullpointerexception.

i not springs, , did basic research. looks like there no code issue , still wonder why beanfactory getting null value.

we tried replacing beanfactory apllicationcontext still same issue.

any appreciated.