Question

i try to deserialize class from the server , but in the client im getting :

java.lang.ClassNotFoundException: com.server.core.StateFilesStruct

where in my client the StateFilesStruct class with this package name:

com.client.core.StateFilesStruct

here is my class’s :

public  Object deserialize(byte[] bytes)   {
        ByteArrayInputStream b = new ByteArrayInputStream(bytes);
        ObjectInputStream o = null;
        try {
            o = new ObjectInputStream(b);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            return o.readObject();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return o;
}

the class im sending this is in the server :

package com.server.core;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Hashtable;

 public class StateFilesStruct implements Serializable {
    private static final long serialVersionUID = 988633010151085730L;
    private Hashtable<String,String> Repository;
    public Hashtable<String, String> getRepository() {
        return Repository;
    }
    public void setRepository(Hashtable<String, String> repository) {
        Repository = repository;
    }
    public StateFilesStruct()
    {
        Repository = new Hashtable<String,String>();
    }
}

the class i keep in the client the same as the server one but with different packge name:

package com.client.core;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Hashtable;

 public class StateFilesStruct implements Serializable {
    private static final long serialVersionUID = 988633010151085730L;
    private Hashtable<String,String> Repository;
    public Hashtable<String, String> getRepository() {
        return Repository;
    }
    public void setRepository(Hashtable<String, String> repository) {
        Repository = repository;
    }
    public StateFilesStruct()
    {
        Repository = new Hashtable<String,String>();
    }
}

and the way im trying to resolve the class in the client is :
receiving from tcpip socket using ZeroMQ

 byte[] byteFileStruct = m_pNetworkManager.getSocket().recv(0); 
 StateFilesStruct stateFilesStruct = (StateFilesStruct)deserialize(byteFileStruct);

getting this exception as you can see its looking fro the server class :

java.lang.ClassNotFoundException: com.server.core.StateFilesStruct
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)

Answer 1

In java, the package name is part of the class name. As far as the JVM is concerned these are 2 completely different classes, so you need to have the same class you’re deserializing in your classpath.