Serialized GregorianCalendar does not perform set(...) correctly

Name: stC104175 Date: 02/25/2000


java version "1.2.2"
Classic VM (build JDK-1.2.2-W, green threads, sunwjit)

A GregorianCalendar that has been obtained by de-serialization (as in RMI) does
not handle the Calendar.set(int field, int value) method correctly. When this
method is used, some fields get reset to a date somewhere in 1970.

The following program creates 2 GregorianCalendar objects one is created with
new, the other is created by serializing and deserializing the first. Calling
the same set(...) method on these two objects demonstrates the problem. Only
the DATE field should be changed, but the YEAR and other fields are lost/set to
strange values.

This is a very nasty bug since it will usually only show up in RMI/EJB
applications. (VERY hard to reproduce!)

---- Start CalBug.java ----
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.io.*;

public class CalBug
{
    public static void main(String[] args)
    {
        Calendar a = new GregorianCalendar();

        Calendar b = null;
        try {
            ObjectOutputStream out = new ObjectOutputStream(new
FileOutputStream("CalBug.ser"));
            out.writeObject(a);
            out.close();

            ObjectInputStream in = new ObjectInputStream(new
FileInputStream("CalBug.ser"));
            b = (Calendar)in.readObject();
            in.close();
        } catch (ClassNotFoundException cnfe) {
            cnfe.printStackTrace();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }

        System.out.println("before a.set(Calendar.DATE, 16): "+a.getTime());
        a.set(Calendar.DATE, 16);
        System.out.println("after a.set(Calendar.DATE, 16): "+a.getTime());

        // Workaround: Uncomment the following line to work around bug
        // b.setTime(b.getTime());

        System.out.println("before b.set(Calendar.DATE, 16): "+b.getTime());
        b.set(Calendar.DATE, 16);
        System.out.println("after b.set(Calendar.DATE, 16): "+b.getTime());
    }
}
---- End CalBug.java ----
(Review ID: 101637)
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