In using javax.swing.JTextField, it throws java.io.NotSerializableException
if a given parameter is a String of Japanese characters (non-ascii characters)
and try to serialize.  JTextField implements Serializable, and when the string
consists of ascii characters, no exception is thrown.

The following code is the sample code showing this synopsis.  Line 6 causes
the exception when the parameter given to the constructor is a String of
Japanese characters (though Japanese characters cannot be shown correctly
in this text field).



     1  import java.io.*;
     2  import javax.swing.*;
     3
     4  public class Test {
     5     public static void main(String[] args)throws Exception {
     6        JTextField ta = new JTextField("Ƚ");
     7        ObjectOutputStream out = new ObjectOutputStream(System.out);
     8        out.writeObject(ta);
     9        out.close();
    10     }
    11  }



% java Test > tmpfile
Exception in thread "main" java.io.NotSerializableException: java.lang.Object
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1054)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:278)
        at java.util.Hashtable.writeObject(Hashtable.java:801)
        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:324)
        at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:795)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1294)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1245)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1330)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1302)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1245)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1330)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1302)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1245)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:278)
        at Test.main(Test.java:8)

N/A

AbstractDocument.MultiByteProperty is an Object. When character > 255 is to
be shown in the text component MultiByteProperty is stored in the attributes
hashtable.

Object is not serializable thus that hashtable not serializable thus text
component not serializable.

The only thing we need from that property is uniqueness. We might use any
serializable object instead of Object. String will do for example


------- AbstractDocument.java -------
1566c1566
<     static final Object MultiByteProperty = new Object();
---
>     static final Object MultiByteProperty = new String();




======================================================================

<     static final Object MultiByteProperty = new Object();
---
>     static final Object MultiByteProperty = "multiByte";

 xxxxx@xxxxx  2004-09-21