Name: joT67522 Date: 11/17/97


The DateFormat class does not appear to be
threadsafe. It is easy to reproduce.
Run the following code. You will get a lot of
StringIndexOutOfBoundsExceptions.
Please advise me if there is a design problem
with my code. Thank you.

Mike Freemon
Sr. Systems Analyst
Information Technology
Illinois Power
Decatur IL USA
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voice: 217-425-4197


import java.text.*;
import java.util.*;

public class Main implements Runnable
{
    private static DateFormat dateFormat;
    private static Thread thr1;
    private static Thread thr2;
    private static Thread thr3;
    private static Thread thr4;
    
public static void main(String args[])
{
        dateFormat = DateFormat.getDateTimeInstance(DateFormat.SHORT,DateFormat.MEDIUM);
        TimeZone tz = TimeZone.getTimeZone("CST");
        dateFormat.setTimeZone(tz);

        thr1 = new Thread(new Main());
        thr2 = new Thread(new Main());
        thr3 = new Thread(new Main());
        thr4 = new Thread(new Main());
        
        thr1.start();
        thr2.start();
        thr3.start();
        thr4.start();
        
        try
        {
            thr1.join();
            thr2.join();
            thr3.join();
            thr4.join();
        }
        catch(Exception e)
        {}
        
} //end of method main
    
    public void run()
    {
        Date ddd = new Date(97,10,12,8,59,0);
        long start = ddd.getTime();
        long i = 0;
        while(true)
        {
            Date dateCurrent = new Date(start + i);
            String sss = dateFormat.format(dateCurrent); //error here
            
            i++;
            if (i%100 == 0) //simple status msg
                System.out.println("count is " + i + "; sss is " + sss);
        }
            
    } //end of method run
    
} //end of class Main
(Review ID: 20178)
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