Question

I’m running into this exception with my code, and I’m not quite to sure on how to fix it. I’m using Apache Tomcat v6.0. I figure that the class “TransactionStorage” needs to implement Serializable, but how do I go around to doing that?

"WARNING: Cannot serialize session attribute sortedList for session 4A5378C83A44BC037B0F1985EAC8DD31
java.io.NotSerializableException: com.middleware.hts.TransactionStorage
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302)
    at java.util.ArrayList.writeObject(ArrayList.java:569)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:592)
    at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:917)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1339)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302)
    at org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1572)
    at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:1015)
    at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:528)
    at org.apache.catalina.session.StandardManager.unload(StandardManager.java:469)
    at org.apache.catalina.session.StandardManager.stop(StandardManager.java:678)
    at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4882)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3454)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:426)
    at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1361)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1653)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1662)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1662)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1642)
    at java.lang.Thread.run(Thread.java:595)

The TransactionStorage class currently looks like this:

public class TransactionStorage implements Comparable<TransactionStorage>{

    private List<HubTransaction> success = new ArrayList<HubTransaction>();

    private List<HubTransaction> failure = new ArrayList<HubTransaction>();

    private List<HubTransaction> undetermine = new ArrayList<HubTransaction>();
    private String process;
    private String client;

    public TransactionStorage(String process, String client){
        this.process = new String(process);
        this.client = new String(client);
    }

    public String getProcess(){
        return this.process;
    }

    public String getClient(){
        return this.client;
    }

    public List<HubTransaction> getSuccess(){
        return this.success;
    }

    public List<HubTransaction> getFailure(){
        return this.failure;
    }

    public List<HubTransaction> getUndetermine(){
        return this.undetermine;
    }

    public void addSuccess(HubTransaction ht){
        this.success.add(ht);
    }

    public void addFailure(HubTransaction ht){
        this.failure.add(ht);
    }

    public void addUndetermine(HubTransaction ht){
        this.undetermine.add(ht);
    }

    public int totalTrans(){
        return this.success.size() + this.failure.size() + this.undetermine.size();
    }

    public int compareTo(TransactionStorage arg) {
        double thisRatio = (double)this.success.size() / (double)this.totalTrans();
        double argRatio = (double)arg.getSuccess().size() / (double)arg.totalTrans();
        if(thisRatio < argRatio){
            return 1;
        }else if(thisRatio > argRatio){
            return -1;
        }else{
            return 0;           
        }
    }

}

Answer 1

java.io.NotSerializableException: com.middleware.hts.TransactionStorage

You need to change

public class TransactionStorage implements Comparable<TransactionStorage>{

to

public class TransactionStorage implements Comparable<TransactionStorage>, Serializable {

where Serializable is java.io.Serializable.