Need explanation on output(Threads).

Question

Hi,
I am new to Threads and need an explanation on the
Output got from the program below.
I executed this program below :
/*================================================
MultiThreadDemo.sqlj
===============================================*/
import java.sql.SQLException;
import java.util.Random;
import sqlj.runtime.ExecutionContext;
import oracle.sqlj.runtime.Oracle;
class MultiThreadDemo extends Thread
double raise;
static Random randomizer = new Random();
public static void main(String []args)
try
Oracle.connect(MultiThreadDemo.class,"connect.properties");
double avgStart = calcAvgSal();
MultiThreadDemo t1 = new MultiThreadDemo(250.50);
MultiThreadDemo t2 = new MultiThreadDemo(150.50);
t1.start();
t2.start();
t1.join();
if(t1.isAlive())
     System.out.println(" Thread t1 is Still Alive");
     t2.join();
if(t2.isAlive())
     System.out.println(" Thread t2 is Still Alive");
double avgEnd = calcAvgSal();
System.out.println("Avg Sal Change : "+(avgEnd-avgStart));
catch(Exception e)
System.out.println("Error running the example : "+ e);
static double calcAvgSal() throws SQLException
double avg;
#sql { SELECT AVG(sal) into :avg from emp};
return avg;
MultiThreadDemo(double raise)
this.raise = raise;
public void run()
System.out.println(" Executing run() ");
     try
System.out.println(" Executing try block in run() ");
     //delay();
     ExecutionContext execCtx = new ExecutionContext();
#sql [execCtx] { UPDATE emp set sal = sal + :raise };
int updateCount = execCtx.getUpdateCount();
System.out.println("Give raise of "+ raise+"to "+updateCount+" employees");
catch(SQLException e)
System.err.println("error updating employees : "+ e);
private void delay()
System.out.println(" Executing delay() ");
try
sleep((long)Math.abs(randomizer.nextInt()/10000000));
catch(InterruptedException e)
==========================================================
===========
Output
============
$ java MultiThreadDemo
Executing run()
Executing try block in run()
Executing run()
Executing try block in run()
Give raise of 250.5 to 7 employees
Give raise of 150.5 to 7 employees
Avg Sal Change : 402.0
=============================
Shouldn't the Output be ??:
=============================
executing run()
executing try block in run()
Give raise of 250.5 to 7 employees
executing run()
executing try block in run()
Give raise of 150.5 to 7 employees
Avg Sal Change : 402.0
================================================
Can anyone explain the Output clearly, as I am
new to Using Threads.
Thanks
Sharath

Answer 1

Reply to my own post:
I think the solution lies in using the "synchronized" keyword for the run() method in order to make it a mutex
and get the o/p as desired.