Monitoring serialization of big objects.

I'm building a comunications architecture for a project that involves the exchange of objects between a client and server (with the usual main+worker threads design). The exchanged messages are sort-of agents that deal with a particular aspect of the application protocol.
The problem is that sometimes we have to send big objects (or send them through a slow link) and I was wondering if there's a way to monitor how many bytes were written to the ObjectOutputStream to generate a progress bar ? (right now we have one in indeterminate mode).
Thanks in advance.

I could re-use Count[I/O]Stream from Jakarta Commons Net.
The serialization of the objets is almost trivial. Even with the complicated messages we never ran into any problems. In fact we have an object that holds a compressed image of another serialized object that gets decompressed whenever a message is sent to the wrapper. It works pretty well.
I guess I'll just keep the current "Doin' something really slow, go get a coffee or something" dialog box :)

Similar Messages

How to Serialize a very big Object??

Please help me !

I misread that as sterilize for a moment. Buckets and buckets of dettol! And that's the clean answer.
As Athena indicates you Serialize a very big Object in exactly the same way that you Serialize a very small object.
Are you encountering a problem, and if so what is it?
Dave.

Serialization big object(100k--2M) into MYSQL database

Hi all !
I have a big object need to be persisted into MYSQL database in my application.
I use two method to meet this request
1 ---- the object implement interface Serializable, but there is serializationVersionID is not same Exception
sometimes.
2 ---- Use XMLEncoder to save my object, the XMLEncoder generate the object XML text about 200k -- 3 M
, but another problem occur :
when I call flush method of XMLEncoder, my application will full ocuppy CPU time, and memory usage will increase to 90M, sometimes will ocurr "Not enough memory" Error.
Why?
can some one help me?
Thanks in advanced

1. You are modifying the signature of one or more of your classes that alters the (system generated) serializationVersionUID and then recompiling. You can declare this for yourself to get control to some extent. See the serialization spec for details.
2. Your object graph is very large, which might be a problem using native or xml formats. Again, the specification details ways in which you can control the serialized form of your objects.
On the information you've provided there's not much more that can be said.

Serialization error for object (IDOC error 51)

hello,
Can Somebody help me with this??? this is what it gives me when the IDOC comes to the receiver instance (SAP R/3). The error code is 51.
Serialization error for object 01,S,12000677 . Expected counter 000001 < 000044 in IDoc
Message no. 5-300
Diagnosis
A serialization error has occurred for the HR object 01,S,12000677 that was received from the logical system E3B.
The expected serialization counter has the value 000001. However, the serialization counter in the IDoc has the value 000044 and is therefore too big. There are therefore older IDocs with this HR object with the serialization counter values in between. These IDocs have either not yet been posted, or have been posted incorrectly.
Procedure
Post all IDocs that have not yet been posted or that were posted incorrectly.
Thank you very much
PM

Hi David,
Please take a look at these threads..
Status code 51
IDOC Status 51
IDoc cannot be opened Error 51 (Inbound)
InfoPackage loading giving IDOC Error: Status 51
cheers,
Prashanth

Is possible to make Serializable a Connection object?

Hi I would like to know if is possible to make Serializable a Connection Object, I would like to save the Connection object into a text file so other class can read it and execute a proper query. If is possible how can I do it?.
Thanks.

Actually, if a class isn't already Serializable, you can't make it become Serializable reliably. Consider the following case:
class A
    int x = 0;
    public void setX(int new_x) { x = new_x; }
    public int getX() { return x; }
class B extends A implements Serializable
    int y = 0;
    public void setY(int new_y) { y = new_y; }
    public int getY() { return y; }
public static void main(String arg[]) throws Exception
    B b = new B();
    b.setX(10);
    b.setY(12);
    someObjectOutputStream.writeObject(b);
}The problem with this is that the implementation of Serializable by class B does not affect class A. In the above example, the ObjectInputStream that obtains the instance of B will have a y value of 12, but an x value of 0 (not 10).
Thus, unless the Connection object implemented Serializable to begin with, it can't become Serializable. And, as the above post has described, the implementers of the Connection object would not make it Serializable as the local Connection object uses underlying O/S resources which cannot simply be transformed into a byte array.

Serialization custom Class Object

Hi,
I'm kind of stuck with a problem.
I've been writing a servlet and applet that are communicating over
internet using a socket connection and Object Serialization.
The objects that are passed are custom:
public class mcuComObj implements Serializable{
    static final long serialVersionUID = 2222;
    private String name;
    private Vector attributes;
    ...There are some more functions but those are not of any interest.
In the vector attributes, I've planted a jPanel (swing).
The weird thing is that this morning, it worked a few times...after that
I'm getting the:
javax.swing.JComponent; local class incompatible: stream classdesc serialVersionUID = 6954663636822719621, local class serialVersionUID = 5896976265092562486 ERROR message.
The send code:
Vector v = new Vector();
Object objButton = (Object) jButton1;
v.add(objButton);
obj.setAttributes(v); //obj = mcuComObj
con.sendObject(obj);   //con = socket connection threadThe receive code:
Object input= (Object) objInpStr.readObject();When I serialize the mcuComObj class, does it also serialize the
embedded objects (in this case that are in the Vector)?
The main question is...how can I solve this? I can not guarantee that
both Servlet and Applet have the same JDK running...!
Have anyone of you got any ideas?
Thanks in advance,
Chris van Diemen

If the "magic numbers" (sent at the beginning of any writeObject() call) on the sending and receiving JDK differ, the object will not de-serialize properly on the receiving end.
The easist solution would be to use a common format to transmit the data. Say! That sounds like XML.
- Saish
"My karma ran over your dogma." - Anon

Serialization vs remote object.

hi, all
come to a crosspoint of selecting which one to use : serialization vs remote object. want to get your inputs. thx for your feedback in advance.
when defining objects like passing parameters or accepting a return value in RMI, there are 2 choices: serialization and remote object. what's criteria to pick up? which choice is the prefered one in industry?
Some use cases:
#1: RMI client needs to create instances of those objects and passes to RMI server
#2: RMI server returnes instances of those objects also.
For case #1, RMI client can't create instance of remote object, right?
thx for help
Tim

#1: RMI client needs to create instances of those
objects and passes to RMI server
For case #1, RMI client can't create instance of
remote object, right?Depends what you want. If you want the methods of the object
to execute on the RMIClient, then you are effectively reversing roles
and the server is acting as a client and you need a remote object.
If you simply want to create an object and pass it to the server
from the client, it just needs to be Serializable.

Reading in memory big objects

Hi
how to read realy big objects (300-500 MB) in memory part by part (better say dynamicaly) - I mean, that you dont have ANY POSSIBILITY read him fully.
Maby it should be buffering, or not - I dont know.
THANK YOU

Out of curiosity, how long would it take someone
to read 500 MB of text?I slaved on the answer, and not so much as a thank
you, go figure. : )
hey drlazlojamf, just out of curiosity, how long
would it take someone
to thank someone else for satiating their incessant
curiosity?Well, let me get out my slide rule. Hmmm... 300 cubits per hogshead...
About now! Thank you TP, you have enlightened all our lives.
The OP seems unrepentant; I thought he'd come back with at least
a "but my manager says its a design requirement". But I guess the
shame was too great. And for that we give thanks.

Could you serialize ANY ObjC object, even those created from scratch ?

I would like to create a custom object that holds a UIImage, CLLocation, two ints and to serialize that single object that wraps all these. Can this be done ? Or serialization of this "container" will fail because this object include ints which cannot be serialized.
Message was edited by: Bracer-J
Message was edited by: Bracer-J

The NSCoder class defines some methods for scalar archiving, for example -encodeInt:forKey:

Need help serialize a collection object

I have a class that's going to manage a list of paths stored as strings as "ArrayList<String> fileList = null;". I can't figure out how to serialize the fileList object. The class that contains the fileList implements Externalizable. here are the read and write functions:
     public void readExternal(ObjectInput in) throws IOException
          fileList = (ArrayList)in.readObject();
     public void writeExternal(ObjectOutput out) throws IOException//, ClassNotFoundException
          out.writeObject(fileList);
     }I've tried lots of different things and nothing works. Anybody know how to serialize an ArrayList? Is ArrayList the best class for the job?

I have a class that's going to manage a list of paths
stored as strings as "ArrayList<String> fileList =
null;". I can't figure out how to serialize the
fileList object. You don't have to do anything to serialize ArrayList, it is already Serializable.
The class that contains the fileList
implements Externalizable. here are the read and
write functions:I will assume there is a good reason this class (that contains the fileList) can itself not be Serializable and needs to be Externelizable.
>
public void readExternal(ObjectInput in) throws
s IOException
          fileList = (ArrayList)in.readObject();
public void writeExternal(ObjectOutput out) throws
s IOException//, ClassNotFoundException
          out.writeObject(fileList);
     }I've tried lots of different things and nothing
works. Anybody know how to serialize an ArrayList? Is
ArrayList the best class for the job?I tried the same example -- with code to make it compilable and testable -- and it works as expected.
What exactly do you mean when you say "nothing works"?

Monitor State of an Object

Is there a way to check the monitor state of an object? For example,
before entering a synchronized block I want to check if there is a monitor on the object and skip the block so the thread is not forced to wait. Thanks in advance.

I don't think so...
But you can use higher-level concurrency constructs to do this. For example, you could design a lock which allowed you to attempt to lock, or give up. Doug Lea has written an excellent book on concurrency, and also has a library of concurrency utilities called "util.concurrent" available online. His page is at:
http://gee.cs.oswego.edu/dl/cpj/
In particular, he has a Semaphore object with a method public boolean attempt(long msecs). You'll also need to use try/finally to make sure you release any locks you acquire.
The book is a great read -- I recommend it.

Serialization of JTree Object

i need to serialize the JTree object .
1) i used XMLEncoder and XMLDecoder
2)and i used ObjectOutputStream and ObjectInputStream
Please help me with sample program
Solution would be really helpful.

krish1985 wrote:
i need to generate the JTree dynamically.for that i need to save the
object in a file(Serialization)Why? I very much doubt you do. The JTree is simply a view on some data. It's that data you want to serialize in some way

Serialization of Vector Object

I have an Message class that is something like
public class Messsage implements Serializable{
int messageCode;
Object payload;
public class dataObject implements Serializable{
int code;
Object referenceObject;
Object other refObject;
The payload is
Vector<Object> testPayload = new Vector<Object> ();
testPayload.add(payloadDescriptionString);
testPayload.add(datadataObject);
msgCode =1;
msg.payload = testPayload;
I am trying to send a vector of different object types in a message through socket streams. I was able to send the Message object through sockets when I didn't set the payload to the vector. Now, I get a NotSerializableExcpetion. Are Vectors not serializable? Is it because my Object Vector has Objects of two or more class types like String and my class? In short what would make a class unserializable? What are the requirements for making it serializable? Any help would greatly appreciated.

Just a footnote. I may have inadvertently solved my problem. I still don't understand it though. In the constructor of my dataObject I instantiated the object to a new object ie
referenceObject = new Object();
otherrefObject = new Object();
Originally, I instantiated them so I could extend this class. I changed the code in the constructor to.
referenceObject = null;
otherrefObject = null;
Serialization appears to be working now. Why does it not serializable in the first place?

Trying to serialize a simple object

Hi,
I can't seem to create an ObjectInputStream. The error is noted in the code below. I also noticd that the output file where I seemingly wrote the object without problems is empty.
import java.io.*;
//Class from which an object is serialized:
class MyClass implements Serializable
     private int num;
     private String str;
     public MyClass(int num, String str)
          this.num = num;
          this.str = str;
     public MyClass()
          num = 0;
          str = null;
     public void show()
          System.out.println(num);
          System.out.println(str);
public class DemoSerialization
     public static void main(String[] args)
          MyClass A = new MyClass(50, "hello serialization");
          A.show();
/*Create output file:*****************/
          File myFile = new File("C:\\TestData\\javaIO.txt");
          try
               myFile.createNewFile();
          catch(IOException exc)
               System.out.println("couldn't create output file");
               System.exit(1);
/*Create output stream:*************/
          ObjectOutputStream out = null;
          FileDescriptor fd = null;     //FileDescriptor represents a connection to a file. Then,
                                                       //you don't have to do all the file checking, etc, when
                                                       //you move the data in the other direction(see below)
          try
               FileOutputStream fos = new FileOutputStream(myFile);
               fd = fos.getFD();
               out =      new ObjectOutputStream(
                              new BufferedOutputStream(fos));
          catch(FileNotFoundException exc)
               System.out.println("couldn't find the file while during creation of file output stream");
               System.exit(1);
          catch(IOException exc)
               System.out.println("io error creating output file stream");
/**/     System.out.println("test1: " + fd); // "java.io.FileDescriptor@df6ccd"
/*Serialize the object:***************/
          try
               out.writeObject(A);
          catch(InvalidClassException exc)
               System.out.println("class definition of object being written to a file has a problem");
          catch(NotSerializableException exc)
               System.out.println("class of the object did not implement Serializable");
          catch(IOException exc)
               System.out.println("general file output error occurred");
/*Create input file stream:***********/
          FileInputStream fis = new FileInputStream(fd);
          BufferedInputStream bis = new BufferedInputStream(fis);
/**/     System.out.println("test2: " + bis); // "java.io.BufferedInputStream@b89838"
          ObjectInputStream in = null;
          try
               in = new ObjectInputStream(bis);      /*****ERROR--throws exception*****/
          catch(IOException exc     )
               System.out.println("ObjectInputStream error");
/**/     System.out.println("test3: " + in); // "null"
/*Read in the object:****************/
          MyClass B = null;
          try
               B = (MyClass) in.readObject(); /***ERROR--NullPointerExecption(see above)***/
          catch(ClassNotFoundException exc)
               System.out.println("no class definition exists in this program for the object read in");
          catch(InvalidClassException exc)
               System.out.println("class def is present but there is something wrong with it");
          catch(StreamCorruptedException exc)
               System.out.println("control info in stream is corrupt");
          catch(OptionalDataException exc)
               System.out.println("attempted to read in a basic data type--not an object");
          catch(IOException exc)
               System.out.println("general stream error occurred during read");
          B.show();
}

Your originaly source did not include the call to the
close method of ObjectOutputStream which is why your
file was created but empty. I assumed you added it
after the call to writeObject.
Well, that isn't the case. I posted that I added flush().
Read the API docs on the FilterDescriptor class.
This class basically represents an opened file (or
r other open streams) in either an inputstream OR
outputstream. So when you close the outputstream.
The file is not open anymore and thus the
e FileDescriptor object is no longer valid because it
represents and open stream.
I didn't have to read the API docs because to me that seemed like common sense: if I have an object that represents a connection to a file, and I close the connection, it makes sense to me that the object would no longer be valid. Therefore, I didn't use close() in my program.
As far as avoiding lots of try blocks, why not wrap
the whole program in a try block? I assume you're
using all those System.out.println commands to help
debug. It'd be more helpful if you called
printStackTrace on the thrown exception when an error
occurs.
Ok, thanks.
I've done some more tests, and the problem isn't specific to serialization. I'm also unable to use a FileDescriptor when reading a char from a file. I get the same "access denied" error:
import java.io.*;
class DemoFileDescriptor
    public static void main(String[] args)
        //Create a file:
        File myfile = new File("C:\\TestData\\javaIO.txt");
        try
            myfile.createNewFile();
        catch(IOException exc)
            System.out.println(exc);
            System.out.println("io exception createNewFile()");
        //Create a FileInputStream:
        FileOutputStream out = null;
        try
            out = new FileOutputStream(myfile);
        catch(FileNotFoundException exc)
            System.out.println(exc);
            System.out.println("error creating FileOutputStream");
        //Get the FileDescriptor:
        FileDescriptor fd = null;
        try
            fd = out.getFD(); //a file connection
        catch(IOException exc)
            System.out.println(exc);
            System.out.println("trouble getting FileDescriptor");
        //Output something to the file:
        char ch = 'a';
        try
            out.write((int) ch);
        catch(IOException exc)
            System.out.println(exc);
            System.out.println("io error writing to file");
        //Create a FileInputStream using the FileDescriptor:
        FileInputStream in = new FileInputStream(fd);
        //Read back from the file:
        char input = ' ';
        try
            input = (char) in.read(); /**ERROR-access denied**/
        catch(IOException exc)
            System.out.println(exc);
            System.out.println("problem reading");
            exc.printStackTrace();
        System.out.println(input);
} Here is the output and stack trace:
---------- java ----------
java.io.IOException: Access is denied
problem reading
java.io.IOException: Access is denied
     at java.io.FileInputStream.read(Native Method)
     at DemoFileDescriptor.main(DemoFileDescriptor.java:69)
Output completed (2 sec consumed) - Normal Termination

Serialization, agents sending objects, possible?

writing objects to a stream is mostly a straight forward task, but what happens if you don't have a stream to write to? This is a sample code from aglets, but it doesn't work any suggestions ? (Anyone know if I should use Jini instead?) :
// The class I want to transfer... How can I serialize this class properly?
public class TransferObject implements java.io.Serializable{
private String name;
private int age;
/** Creates a new instance of TransferObject */
public TransferObject(String name, int age) {
this.name = name;
this.age = age;
public String getName() {
return name;
public int getAge() {
return age;
// The mother aglet, that will create a child aglet
public class MotherAglet extends Aglet{
public void run()
URL codebase;
try{
codebase = new URL("atp://PC06");
     TransferObject tO = new TransferObject("This is transferobject", 1);
     // createing a ChildAglet , sending the tO refernce
getAgletContext().createAglet(codebase, "ChildAglet", tO);
}catch(Exception e) {
System.out.println(e.getMessage() + "Creation went wrong");
public class ChildAglet extends Aglet{
public void onCreation(Object init) {
TransferObject tO = null;
try{
tO = (TransferObject)init;
}catch(Exception e) {
System.out.println(tO.getName());
If I had added the properties of TransferableObject reference in a Vector and re - initiated a new Object at ChildAglet this will work, but it would be easier to just transfer the object directly. Is there a way of doing this ?

I had a problem with this Aglet.
import com.ibm.aglet.*;
import com.ibm.aglet.util.*;
import com.ibm.agletx.util.SeqPlanItinerary;
import java.util.* ;
public class GatherInfo extends Aglet {
StringBuffer buffer;
SeqPlanItinerary itinerary;
public void onCreation(Object ini) {
itinerary = new SeqPlanItinerary(this);
itinerary.addPlan("atp://marcus:500/", "getLocalInfo");
itinerary.addPlan("atp://marcus:501/", "getLocalInfo");
// return to host and print result
itinerary.addPlan(getAgletContext().getHostingURL().toString(),"pr
intResult");
this.start() ;
public boolean handleMessage(Message msg) {
if (msg.sameKind("getLocalInfo")) {
getLocalInfo(msg);
return true;
} else if (msg.sameKind("printResult")) {
System.out.println(buffer);
return true;
return false;
public void run() {
System.out.println("Hello, just visiting...") ;
public void oncemore() {
try {
itinerary.startTrip();
} catch (Exception ex) {
ex.printStackTrace();
public void start() {
buffer = new StringBuffer();
oncemore();
public void getLocalInfo(Message msg) {
AgletContext ac = getAgletContext();
setText("Here I am about to gather info, and waiting ...") ;
// waitMessage(2 * 1000);
buffer.append("I've been to " + ac.getHostingURL().toString() +
"\n") ;
buffer.append(new LocalInfo().getAll()) ;
buffer.append("\n") ;
When execute this code show me the next error
java.io.exception: FileNotFound c:\aglets-2.02\public\[Ljava\lang\objec; .class
I need help, what is this?

Monitoring serialization of big objects.

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