Why does the execution order between the printStackTrace() and the other methods appear to be nondeterministic?
java, printstacktrace
Solution
It is because `printStackTrace` writes in `System.err` while `System.out.println` writes on `System.out`. Even if both `System.err` and `System.out` use the same underlying resource for the output messages (e.g. the same file or the same console), they flush at different moments.
If you want to have a synchronized output, write the exceptions in `System.out` as well:
e.printStackTrace(System.out);
Or even better, use a logger, which already synchronizes the outputs into a shared resource and give you more options about what's being output in the message e.g. Class, method, date and time, thread name, etc. among other benefits like writing log messages in database instead of a text file, and on.
Problem
In my code snippet below, the `printStackTrace()` method is called in the `catch block`. After running the program you can see that sometimes the `printStackTrace()` runs several times in a row instead of running in the order of `printStackTrace()` --> `catch block` --> `finally block`. If you change the `static boolean b` to `false` then the `System.out.print(e)` executes in order. So why does the `printStackTrace()` behaves in different way? (something with the threads??) ``` public class PrintStackTrace { static boolean b = true; public static void main(String[] args){ for(int i = 0; i < 100; i++){ try{ throw new Exception("[" + i + "]"); } catch(Exception e){ if(b){ e.printStackTrace(); } else{ System.out.print(e); } System.out.print(" Catch: " + i); } finally{ System.out.print(" Finally: " + i); } System.out.println(); } } } ```