javax.ejb.EJBException: Error while sending a request[Caused by: java.io.OptionalDataException]

Question

I have an EJB call from client side like this:

Portfolio[] ptfTab = ServicesMgr.getInstance().getPortfolioService().getPortfolios();

getPortfolioService() returns an instance of PortfolioFinderDelegate (EJB client interface). The EJB service from client side has this signature:

public interface PortfolioFinder extends IBasic {
   Portfolio[] getPortfolios();
}

For the EJB on server side, the implementation of the method is:

public Portfolio[] getPortfolios() {
    List<Portfolio> portfolioList = getPortfoliosAsList();
    return portfolioList.toArray(new Portfolio[portfolioList.size()]);
}

The method getPortfolioAsList() is a private method:

 private List<Portfolio> getPortfoliosAsList() {
     List<Portfolio> portfolioList = new ArrayList<Portfolio>();
     LOCK.readLock().lock();
     try {
          List<String> keys = portfolioCache.getKeys();
          for (Iterator<String> iterator = keys.iterator(); iterator.hasNext();) 
              {
               String codeport = iterator.next();
               Set<Portfolio> s =(Set<Portfolio>) portfolioCache.get(codeport) .getValue();
               portfolioList.addAll(s);
              }
         } catch (Throwable e) {
                LOGGER.error(e.getMessage(), e);
         } finally {
                LOCK.readLock().unlock();
         }

         return portfolioList;
   }

Yesterday, I got a strange stack trace like this, I have never encountered it before and I am sure the portfolio cache on server side is not empty. Besides, there is no error log on server side. When the first client encounters this error, all the client have it then. Is this issue related to the size of the returned object? (because the cache size is increasing every day) Is there a limit of object size when data are serialized and deserialized through EJB?

2019-02-26 14:51:35 ERROR [StartupMgr][EJBPortfolioMgr.java:57] : Error while sending a request
javax.ejb.EJBException: Error while sending a request
                at org.ow2.easybeans.proxy.client.ClientRPCInvocationHandler.invoke(ClientRPCInvocationHandler.java:205)
                at org.ow2.easybeans.proxy.client.ClientRPCInvocationHandler.invoke(ClientRPCInvocationHandler.java:117)
                at com.sun.proxy.$Proxy33.getPortfolios(Unknown Source)
                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at com.clam.mediaplus.client.services.ProxyRemoteObject.invoke(ProxyRemoteObject.java:87)
                at com.sun.proxy.$Proxy33.getPortfolios(Unknown Source)
                at client.delegate.common.PortfolioFinderDelegate.getPortfolios(PortfolioFinderDelegate.java:46)
                at com.casits.rambo.dao.portfolio.EJBPortfolioMgr.reload(EJBPortfolioMgr.java:42)
                at com.casits.rambo.dao.portfolio.AbstractPortfolioMgr.<init>(AbstractPortfolioMgr.java:24)
                at com.casits.rambo.dao.portfolio.EJBPortfolioMgr.<init>(EJBPortfolioMgr.java:31)
                at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
                at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
                at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
                at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
                at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:126)
                at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:72)
                at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:948)
                at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:901)
                at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
                at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
                at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
                at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
                at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
                at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
                at com.casits.rambo.dao.common.CommonBeanFactory.getPortfolioMgr(CommonBeanFactory.java:54)
                at com.casits.rambo.dao.portfolio.PortfolioMgr.getAttribPortfolio(PortfolioMgr.java:82)
                at com.casits.rambo.dao.portfolio.PortfolioMgr.getAttribPortfolio(PortfolioMgr.java:151)
                at com.casits.rambo.dao.portfolio.PortfolioMgr$2.processRow(PortfolioMgr.java:217)
                at org.springframework.jdbc.core.JdbcTemplate$RowCallbackHandlerResultSetExtractor.extractData(JdbcTemplate.java:1408)
              at org.springframework.jdbc.core.JdbcTemplate$1QueryStatementCallback.doInStatement(JdbcTemplate.java:445)
                at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:395)
                at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:455)
                at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:459)
                at com.casits.rambo.dao.portfolio.PortfolioMgr.getAllAttribPortfolios(PortfolioMgr.java:207)
                at com.casits.attrib.refptf.controller.RefPortfolioMgr.getAllAttribCodeports(RefPortfolioMgr.java:257)
                at com.casits.attrib.refptf.controller.RefPortfolioMgr.refreshAttribCodeports(RefPortfolioMgr.java:243)
                at com.casits.attrib.refptf.controller.RefPortfolioMgr.init(RefPortfolioMgr.java:221)
                at com.casits.attrib.refptf.controller.RefPortfolioMgr.<init>(RefPortfolioMgr.java:239)
                at com.casits.attrib.refptf.controller.RefPortfolioMgr.<clinit>(RefPortfolioMgr.java:191)
                at com.casits.attrib.refptf.RefPtfModule.init(RefPtfModule.java:80)
                at com.casits.attrib.attribcommon.AbstractModule.load(AbstractModule.java:70)
                at com.casits.attrib.main.MainJFrame.executeEnableModule(MainJFrame.java:418)
                at com.casits.attrib.main.MainJFrame.addModule(MainJFrame.java:336)
                at com.casits.attrib.main.MainGUI.createAndShowGUI(MainGUI.java:80)
                at com.casits.attrib.main.StartupMgr.init(StartupMgr.java:82)
                at com.casits.attrib.attribcommon.manager.AttribUserMgr$1.run(AttribUserMgr.java:390)
                at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: Error while handling answer on the remote side 
                at org.ow2.easybeans.rpc.rmi.client.RMIClientRPC.sendEJBRequest(RMIClientRPC.java:116)
                at org.ow2.easybeans.proxy.client.ClientRPCInvocationHandler.invoke(ClientRPCInvocationHandler.java:202)
                ... 49 more
Caused by: java.rmi.UnmarshalException: IOException unmarshalling returnjava.io.OptionalDataException; nested exception is: 
                java.io.OptionalDataException
                at org.ow2.carol.rmi.jrmp.server.JUnicastRef.performRemoteCall(JUnicastRef.java:212)
                at org.ow2.carol.rmi.jrmp.server.JUnicastRef.invoke(JUnicastRef.java:161)
                at org.ow2.easybeans.rpc.rmi.server.RMIServerRPCImpl_Stub.getEJBResponse(RMIServerRPCImpl_Stub.java:60)
                at org.ow2.easybeans.rpc.rmi.client.RMIClientRPC.sendEJBRequest(RMIClientRPC.java:114)
                ... 50 more
Caused by: java.io.OptionalDataException
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1370)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at java.util.HashMap.readObject(HashMap.java:1179)
                at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at java.util.HashMap.readObject(HashMap.java:1180)
                at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at java.util.HashMap.readObject(HashMap.java:1180)
                at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at java.util.HashMap.readObject(HashMap.java:1180)
                at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at java.util.HashMap.readObject(HashMap.java:1180)
                at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:606)
                at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1706)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1344)
                at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
                at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
                at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
                at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
                at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
                at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:325)
                at org.ow2.carol.rmi.jrmp.server.JUnicastRef.performRemoteCall(JUnicastRef.java:205)
                ... 53 more

Answer 1

In short, in our application code a complex value object (used as a return value for remote method invocations) had a HashMap datastructure as an internal field. After changing the type of this field to ConcurrentHashMap the OptionalDataExceptions stopped occurring. It seems that somewhere in the legacy code this Map is handled in non thread-safe way.