🚀 go-pugleaf

No that is not a sufficient solution.  Synchronized just means 2 threads
cant call that code at the same time.  However, you failed to synchronize
the method below.  Remember, you are synchronizing with respect to temp2
actually.

public void setTemp2(int temp2) {this.temp2 = temp2;}

AS a result it can be called anytime, even while another thread is in the
synchronized section you created below

>     synchronized {
>       temp2 = x / 3;
>       return temp1 + temp2;
>     }


In otherwords, 2 threads cant enter the synchronized section you created
which does add necessary safety, but 1 thread could be in that section,
while another is calling setTemp2, which would again be thread unsafe.

better is

public synchronized void setTemp2(int temp2) {this.temp2 = temp2;}
or
public void setTemp2(int temp2) { synchronized {this.temp2 = temp2;}}

with

   public int performCalculation(int x, int y) {
     int temp1 = 0;
     temp1 = y + 5;
synchronized
{
     temp2 = x / 3;
     return temp1 + temp2;
}
   }


Also
 public int performCalculation(int x, int y) {
     int temp1 = 0;
     temp1 = y + 5;
synchronized(temp2)
{
     temp2 = x / 3;
     return temp1 + temp2;
}
   }

good luck




Synchronizing is taxing.  Try not to synchronize in loops whenever
possible!!

"Zoltan Grose" <zgrose@pacbell.net> wrote in message
news:3b1b28df$1_2@dnews...
> I'm going to be diving into servlet programming shortly and I feel now is
a
> good time to wrap my brain around threads and the keyword synchronized.
>
> From the reading I have done and the examples I have seen, I believe I can
> summarize the use of synchronized in this way:
>
> "If a method accesses (either reads from or writes to) a variable that one
> reasonably expects not be constant and that variable is not local to the
> method, the accessing code should be synchronized."
>
> For example, I believe this code to be thread-safe since all of the
> variables are local.
>
> public class MyClass {
>   public int performCalculation(int x, int y) {
>     int temp1 = 0; int temp2 = 0;
>     temp1 = y + 5;
>     temp2 = x / 3;
>     return temp1 + temp2;
>   }
> }
>
> I believe this code to be thread-unsafe since temp2 is not local to the
> method and could potential be modified at any point during any execution
of
> performCalculation.
>
> public class MyClass {
>   int temp2 = 0;
>   public void setTemp2(int temp2) {this.temp2 = temp2;}
>   public int performCalculation(int x, int y) {
>     int temp1 = 0;
>     temp1 = y + 5;
>     temp2 = x / 3;
>     return temp1 + temp2;
>   }
> }
>
> The second example would be made thread-safe again by wrapping the unsafe
> section in a sychronized block.
>
>     synchronized {
>       temp2 = x / 3;
>       return temp1 + temp2;
>     }
>
> Am I on the right track? (Am I in the right newsgroup?) My background is
in
> VB, so threads are one of the new concepts I'm trying to deal with before
I
> get to deep. Thanks in advance.
>
> -zoltan
>
>
>