Kendi Balazs Kendi Balazs - 4 months ago 11
Java Question

JavaEE - InvalidClassException

I'm writing a JavaEE application and I have the following problem: if I initialize any new variable in one of the classes (TraceMessage) and start the application, I am getting the following error:

java.io.InvalidClassException: com.nsn.extmon.util.TraceMessage; local class incompatible: stream classdesc serialVersionUID = -5424907704652912574, local class serialVersionUID = -5748024201087063218
at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:612)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1630)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1521)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1779)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1353)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
at java.util.ArrayList.readObject(ArrayList.java:771)
at sun.reflect.GeneratedMethodAccessor355.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:1058)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1907)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1806)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1353)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
at com.nsn.extmon.databaseHandling.ResultDataHandler.getTraceMessages(ResultDataHandler.java:137)
at com.nsn.extmon.util.TraceResultBean.traceRead(TraceResultBean.java:50)
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 org.apache.el.parser.AstValue.invoke(AstValue.java:278)
at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
at org.apache.myfaces.view.facelets.el.ContextAwareTagMethodExpression.invoke(ContextAwareTagMethodExpression.java:96)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:72)
at javax.faces.component.UICommand.broadcast(UICommand.java:120)
at org.richfaces.component.RowKeyContextEventWrapper.broadcast(RowKeyContextEventWrapper.java:104)
at org.richfaces.component.UIDataAdaptor.broadcast(UIDataAdaptor.java:452)
at javax.faces.component.UIViewRoot._broadcastAll(UIViewRoot.java:1013)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:284)
at javax.faces.component.UIViewRoot._process(UIViewRoot.java:1302)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:745)
at org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:38)
at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:170)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:197)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.nsn.extmon.authentication.LoginFilter.doFilter(LoginFilter.java:33)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:611)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1721)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1679)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)


I have no idea what this error is, I only know that if I modify variable names, then everything is working fine. The error only comes up when I'm declaring new variables.

Thanks in advice.

Answer

An InvalidClassException class exception occurs in this situation when you deserialise (receiving, loading, etc) an object into a java process that has a different version of the class as the one used during serialisation (sending, saving, etc) .

It looks like you are saving objects into the database (com.nsn.extmon.databaseHandling.ResultDataHandler?). I think there are serialised blobs in the database serialised with a different version of the class ("adding fields") then when you read them from the database again.

If you are adding fields, you should keep the serialVersionUID the same (for non contract-breaking changes)

For Example

public class TraceMessage implements Serializable {

  private static final long serialVersionUID = 1L;
  …
}

If it is a contract-breaking change, then you must make sure you have the same class version on both ends.

if you are sending messages between applications, then you might also want to look in a less brittle protocol such as google protobuf.

EDIT (see comments): If you want to load the old classes stored in your database with the new class, then set your serialVersionUID to -5424907704652912574

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