🚀 go-pugleaf

Zoltan,

yes, you are on the right track.
Your examples are all fine except that your second one needs one more
synchronization around the setTemp2 method. All read/write access of shared
data must be guarded to get effective synchronization.

In case you didn't see this tutorial yet:
http://web2.java.sun.com/docs/books/tutorial/essential/threads/index.html

Torsten

Zoltan Grose schrieb in Nachricht <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
>
>
>