Javabean implements java.io.serializable interface

Hi All
According to Javabean specification,Section 5.4, it states that javabean components persistence is done through source code generation to reinitialize bean component's state.
What happen's if a person is used a text editor and not an IDE to write the bean classes.
Pls reply asap.
Thanks n regards
Divya

JavaBeans spec says that it is an alternative way that depends on builder tools. Nothing wrong will happen.

Similar Messages

A Bean must implement the java.io.Serializable interface? What makes the di

Hi, I have took an example from sun notes on JavaBeans (you can find the example here http://java.sun.com/developer/onlineTraining/Beans/beans02/page2.html). The code is like this.....
import java.awt.*;
import java.io.Serializable;
public class SimpleBean extends Canvas
                 implements Serializable {
private Color color = Color.green;
//getter method
public Color getColor() {
     return color;
//setter method
public void setColor(Color newColor) {
     color = newColor;
     repaint();
//override paint method
public void paint (Graphics g) {
     g.setColor(color);
     g.fillRect(20,5,20,30);
//Constructor: sets inherited properties
public SimpleBean() {
     setSize(60,40);
     setBackground(Color.red);
}I didn't find any difference in executing the program by implementing the Serializable interface and without implementing. On choosing serialize component in the File Menu, I serialized the component after changing its color (property), and saved as .ser file. And created the .Jar file including .ser file. when I load the jar file and place the bean in the beanbox, it is showing the bean that is updated. This can be done by implemeting Serializable interface and without implementing Serializable interface also. And I have a statement that has been given in the notes provided by SUN. That is ' Bean must implement the Serializable interface. Objects that support this interface can save and restore their state from disk '. I couldnot come up with the summation of this statement.
Anyone who has an idea... please give an explanation.
Thank you.

Maybe you should show us your coding how you saved your beans state.
Are you serious that you save the special object? Or do you save the values of the object into a file and load those values into a new object?

How serialization happens in java thru serializable interface??

Hi,
Can anybody plz tell me what are the advantages of having a blank interface??
One example of blank interface is Serializable interface in java. Serializable being a blank interface allows you to perform persistence in java framework just by implementing it. Just curious to know how the blank interface (Serializable) does the serialization in java???
Tx in Advance
Jameel

Serializable is a marker interface. It simply indicates that any object that has instanceOf Serializable returning true can be serialized. By implmenting this interface you declare that your class is serializable.

Implementation of java.lang.Serializable writeObject()

Hi,
Who (what class) provides the implementation for writeObject() and readObject() for java.lang.Serializable Interface?
And in general for these Interfaced (Somewhere called Marker Interface), how does the implementation applies?
How do they distinguished from other Interfaces?

>
Who (what class) provides the implementation forwriteObject() and readObject() for
java.lang.Serializable Interface?
And in general for these Interfaces (Somewhere called
Marker Interface), how does the implementation
applies?
How do they distinguish from other Interfaces?
The Serializable interface is a marker interface because it doesn't require the programmer to implement any methods whasoever, so the syntax:
class MyClass implements Serializable { }
is perfectly legal.
This just tells the compiler that al objects of type MyClass will be serializable. No class provides the implementations for readObject() and writeObject(), you'll have to do that yourself. Or, more exactly, it is (strongly) recommended to do that, if you want to control what is and isn't serialized (you may have sensitive members in your class, that you don't want to be serialized!)
Ok, these 2 methods are defined somewhere (I don't have the Java Serialization specification with me right now :( ), you have to implement them to give you better control of what's going on. Inside these methods you'l want to use the readObject() and writeObject() methods of other types).
I'll come back later with a full example.
Yuo may want ot check out the Java Serialization Specification (available for download on the Sun website)

Why do we use java.io.serializable

i was studing javabeans. i found out we implements java.io.serializable.
can anyone explain why do we use it?
S

Being serializable, it is then able to have a form of permanence... ie. it can be saved to disk. Then when your app/applet/service etc restarts, it can load the saved data to be used again.

Comparable and Serializable interfaces

Hi All,
I have developed a program in java which implements Comparable and Serializable Interfaces. After, I decided to run the program in J2ME. But later on, I found that MIDP doesn't implement these interfaces.
Some one can help me how to implement my own interfaces.
Thank you

Hi Supareno
I need urgently your help.
I developed Java program which works as predicitive text system for my mother tongue.I would like to move from Java to J2ME. But until now I have problems. please can u help me. the following code run in command line.
I tried to develop my own interfaces as you told me but it doesn't work.
Help me also for reading and writing text files.
Thank you
import java.util.*;
import java.io.*;
import java.util.Vector;
import java.util.Enumeration;
public class PredText {
private Vector dict;
public static final String dictionaryFile = "C:/java/words.txt";
// convert a string to the corresponding signature
public static String toNumeric (String word) {
String lowerWord = word.toLowerCase();
StringBuffer result = new StringBuffer("");
for (int i = 0; i < lowerWord.length(); i++) {
char c = lowerWord.charAt(i);
if ("abc".indexOf(c) > -1) result.append("2");
else if ("def".indexOf(c) > -1) result.append("3");
else if ("ghi".indexOf(c) > -1) result.append("4");
else if ("jkl".indexOf(c) > -1) result.append("5");
else if ("mno".indexOf(c) > -1) result.append("6");
else if ("pqrs".indexOf(c) > -1) result.append("7");
else if ("tuv".indexOf(c) > -1) result.append("8");
else if ("wxyz".indexOf(c) > -1) result.append("9");
else if (" ".indexOf(c) > -1) result.append("9");
else result.append("?");
return result.toString();
// find all the words corresponding to a signature
public Vector findMatches(String sig) {
WordSig ws = new WordSig(sig, "");
WordSig newws;
Vector results = new Vector();
int index;
index = Collections.binarySearch(dict, ws);
if (index < 0){
// no matches! :(
// try to get the string that starts with a substring like ours.
index=-1-index;
if (((WordSig)dict.get(index)).getSig().startsWith(sig)) {
// no word found. we return those starting with the
// same signature
newws = (WordSig) dict.get(index);
results.addElement(newws.getWord().substring(0,sig.length()));
return results;
} else{
//no match
return results;
} else {
// go back to the first match
while(((WordSig)dict.get(index)).getSig().equals(sig) && index>0)
index--;
if (index != 0)
index++;
while ((newws = (WordSig) dict.get(index)).equals(ws)){
results.addElement( newws.getWord() );
index++;
return results;
// intialises the dictionary
public PredText () {
     String word;
String sig;
Vector dict = null;
// first try to load dict.dat
try {
System.out.print("Trying to load dict.dat...");
FileInputStream fileStream = new FileInputStream("C:/java/dict.dat");
ObjectInputStream objectStream = new ObjectInputStream(fileStream);
dict = (Vector) objectStream.readObject();
fileStream.close();
System.out.println(" done.");
}catch (ClassNotFoundException classNotFoundException) {
     System.out.println("Unable to create an object");
catch (IOException e) {
// exception: create the dictionary
System.out.println("Error. I'm going to recreate the dictionary file");
try {
dict = createDict();
catch (IOException ioe) {
System.err.println("Error while creating dictionary file. Exiting." + e);
System.exit(1);
this.dict = dict;
// create the dictionary serialised file
public Vector createDict () throws IOException {
String word;
Vector dict = new Vector();
//open the dictionary file
System.out.print("Reading the dictionary... ");
BufferedReader dictFile = new BufferedReader(
new FileReader(dictionaryFile));
//insert each word into the data structure
while ((word = dictFile.readLine()) != null) {
word = word.toLowerCase();
dict.addElement(new WordSig(toNumeric(word), word));
// List list = dict.subList(0, dict.size());
List list = dict.subList(0, dict.size());
Collections.sort(list);
System.out.println("done.");
System.out.print("Writing the dictionary... ");
FileOutputStream fileStream = new FileOutputStream("C:/java/dict.dat");
ObjectOutputStream objectStream = new ObjectOutputStream(fileStream);
objectStream.writeObject(dict);
objectStream.flush();
fileStream.close();
System.out.println("done.");
return dict;
public static void main (String args[]) {
     PredText pt = new PredText();
if (args.length == 0) {
// no arguments, find the largest clash
     Vector result;
     Enumeration e = pt.dict.elements();
String currentSig = "";
String prevSig = "";
int clash = 0;
int maxClash = 0;
String clashSig = "";
while (e.hasMoreElements()) {
WordSig ws = (WordSig) e.nextElement();
currentSig = ws.getSig();
if (currentSig.equals(prevSig)) {
// another word with the same signature
clash ++;
} else {
// new signature: check if the previous one led
// to a maximal clash
if (clash > maxClash) {
clashSig = prevSig;
maxClash = clash;
clash = 1;
prevSig = currentSig;
result = pt.findMatches(clashSig);
System.out.println("The signature leading to most clashes is "
+ clashSig + " with " + result.size() +
" number of clashes");
for (int j = 0; j < result.size(); j++) {
System.out.println((String)result.get(j));
} else if ("0123456789".indexOf(args[0].charAt(0)) > -1){
// numeric input: find the matches for the argument
Vector result;
result = pt.findMatches(args[0]);
for (int j = 0; j < result.size(); j++) {
System.out.println((String)result.get(j));
} else {
// convert each word to the corresponding signature
for (int i = 0; i < args.length; i++) {
System.out.print(toNumeric(args) + " ");
class WordSig implements Comparable, Serializable {
String word;
String sig;
public WordSig (String sig, String word) {
this.sig = sig;
this.word = word;
public String getSig () {
return this.sig;
public String getWord() {
return this.word;
public int compareTo (Object ws) {
return sig.compareTo(((WordSig) ws).getSig());
public boolean equals (Object ws) {
return sig.equals(((WordSig) ws).getSig());
public String toString () {
return sig + ", " + word;

Comparable and Serializable Interfaces in MIDP

Hi All,
I have developed a program in java which implements Comparable and Serializable Interfaces. After, I decided to run the program in J2ME. But later on, I found that MIDP doesn't implement these interfaces.
Some one can help me how to implement my own interfaces.
Thank you

Thank you for replying to me.
My problem is to compare to objects in MIDP.
You know that in java is possible to implements directly the Comparable interface but in MIDP is not the same. So I think it requires to create your own. Is that my question.
I need some to help me. just to avoid the implentation of comparable interface from the java lang package.
Thank u.

Functionality to generate UUID (for Serializable interface)

When working with custom components, the java.io.Serializable interface often is a must. Eclipse always complains about the missing UUID-attribute. There are a few plugins around to generate them, but an integrated solution in NitroX would be really cool.

Eclipse 3.1 will offer you the option to generate serials for you if you open the Quick Fix menu for the warning.PERFECT. :D :D Thanks for the hint. So we only have to wait for NitroX fro 3.1 :twisted:
Apart from that I would claim it's hardly a feature in the scope of NitroX.Well. Yes an no.
As lots of the objects that one uses in the context of the session, or as objects that should be sent over the wire (state=client) in JSF, it is in the scope of every plugin or IDE that wants to help the developer develop JSF-application, therefor it is in the scope...
But with Eclipse providing it already (soon...) it is no discussion any more.
regards
Alexander

Example class that implements Serializable interface

Dear,
I have a class myData that I want to implement Serializable interface. class myData has only two fields: Integer iData1, String sData2.
Could anybody shown me how my myData class should be?
Thanks a lot!

Hey, if you have yet to obtain a remote reference from the app server ...then we are into pandora's box. I lost three whole heads of hair getting up on JBoss when I first started. You want to check out the JBoss forums on the JBoss website, and the enterprise javabeans forum here. Search some posts and read the free JBoss manual.
Unfortunately, there isn't a 'here, do this' solution to getting connected with JBoss. There are quite a few gotcha's. There are descriptors, descriptor syntax ...and this changes between releases so there seems to be alot of people saying 'here, do this' ...but you try and it doesn't work (wrong release). Here are some descriptors that I threw up recently for someone ...a place to start.
http://forum.java.sun.com/thread.jsp?forum=13&thread=414432
This drove me nuts until it all worked right. I was stuck for three weeks at one point ...ready to give up, but then I got it. Perservere ...its a nice container for learning in (its free!).
I will try and watch for you.
Oh, and put something in your head ...at least then you will keep your hair !
:)

Implementing the Serializable interface

Hi guys,
I have a conceptual question about implementing the Serializable interface - since it's only a marker interface (i.e. - it doesn't have any abstract methods) why does Java demand an object to implement this interface in order to be written into a file? What I'm asking is why wouldn't they make the writeObject method's signature
public void writeObject(*Object* o)
so any object can get in? What is the point of forcing a class to implement an interface in order to enable it to be written to a file?

So that serialization requires the explicit consent of the class or superclass/superinterface.

Why we require to implement Serializable interface?

Hi techies,
I am new to Serialization. Why we require to use Serializable interface for Serializing objects. Since Serializable interface is a marker interface, how it prevents objects not implementing Serializable from being Serialized. Does Java Compiler checks it or how it checks it?

JavaBreather wrote:
Since Serializable interface is a marker interface, how it prevents objects not implementing Serializable from being >Serialized. Does Java Compiler checks it or how it checks it?Compiler does nothing but mark the class as implementing the interface. You can then later check whether objects instanceof Interface" and find out whether or not it is present. As said above, ObjectOutputStream does the same thing.
Marker interfaces are a misuse of interfaces, and should be avoided. You shouldn't create new ones.Annotations introduce in Java 5 are a generic mechanism of adding metadata to a class.

What is the use of Serializable Interface in java?

Hello friends,
I have one dout and i want to share with u guys:
Why Serializable interface made and actully
what's the use of it?
At which place it become useful ?
It is not contain any method then why it is made?
If anyone have any idea about this then please reply.
Thanks in advace
Regards,
Jitendra Parekh

t is not contain any method then why it is made?To point out to the user of a class (and the programs) that the design of this class is conforming to certain restraints needed for Serialization.

Serializable interface

I have a dount about with Serializable
Serializable interface does not have any methods or varialbles, then how can a class be serialized just by implementing Serializable interface. What is happening internally in Java to make this. Pls clear my doubt.
Thanks
Srinivas

Can U pls brief about reflectionSun has a tutorial on reflection that might interest you:
http://java.sun.com/docs/books/tutorial/reflect/index.html

Why do we need Serializable Interface since there is no method decl. inside

On working with Serialization in java
I could see that the Serializable Interface is empty without any method inside.
Also, the writeObject() and readObject() accepts only if the Serializable interface is implemented to a class.
What is the use of implementing an empty Interface?
Please clarify.
Thanks in advance.
Regards,
R.Mahendra Babu

The completely empty Serializable is only a marker interface -- it simply allows the serialization mechanism to verify that the class is able to be persisted.

Why does serializable interface has no methods inside it

Aloha
Can anyone please help me with this....Serializable interface has no methods inside it.So how is it useful to the user.Also if I am writing a class which implements Serializable how does JVM know what to do.?

JoachimSauer wrote:
dannyyates wrote:
[The JVM] doesn't know about serialisation [...]Sorry for the nitpick, but that's not completely true. The JVM needs to know about serialisation at least at little bitNo.
since Serialization creates new objects without the code from the constructrs ever being run. ObjectInputStream loads the classes just like any other code would, although it's obviously reading the serialized stream to get that information... and then calls newInstance() on ObjectStreamClass.
And ObjectStreamClass uses reflection to get a constructor (via java.lang.Class getDeclaredConstructor ) and then uses said java.lang.reflect.Constructor to create a new instance via newInstance()
There is no JVM magic. It is all Java code. (With the exception of what java.lang.reflect.Constructor does because at the point it dives into sun packages but you could do the same by calling java.lang.reflect.Constructor)

Javabean implements java.io.serializable interface

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