NetBeans - printStackTrace and output mixed

Question

I have built a simple test routine to play around with exceptions and how they work:
    private static void testExceptions(int i)
        try
            if (i==1 || i==2) System.out.println(1/0);
            if (i==3 || i==4) throw new UnsupportedOperationException("Not yet implemented");
        catch (UnsupportedOperationException e)
            e.printStackTrace();
        finally
            System.out.println("Always called - if errors occur or not.");
            //next statement causes exception to be cleared
            //(no error/exception reported to caller!)
            if (i==1 || i==3) return;
    }Before I call that method I do some output with System.out.println("...");
Then I call testExceptions(3);
When I run this I get different output, e.g.:
Starting program...
System temp folder: F:\Temp
java.lang.UnsupportedOperationException: Not yet implemented
        at at.mwildam.testprj.Main.testExceptions(Main.java:442)
User name: mwildam
        at at.mwildam.testprj.Main.main(Main.java:173)
User home dir: C:\Dokumente und Einstellungen\myuserid
App language: de
Starting tests...
Always called - if errors occur or not.
Tests finished.How can this be? - The expected output would be in my opinion:
Starting program...
System temp folder: F:\Temp
User name: mwildam
User home dir: C:\Dokumente und Einstellungen\myuserid
App language: de
Starting tests...
java.lang.UnsupportedOperationException: Not yet implemented
        at at.mwildam.testprj.Main.testExceptions(Main.java:442)
        at at.mwildam.testprj.Main.main(Main.java:173)
Always called - if errors occur or not.
Tests finished.And actually when running this from the commandline (not in the IDE) then that is exactly the output - as expected. What goes wrong here?

Answer 1

I imagine that the printStackTrace is not the best
solution in general (apart from quick test
applications) - maybe I should in general write debug
output and error messages to a file - then I should
not experience the problem and get reliable output
even when in IDE - do you agree to that?Use a logging framework. Never consider "running your app in an IDE" to be a worthwhile or reliable test. Users don't run apps in IDEs, do they?
Or what other "best practices" are around?
I have seen some logger classes that are available.
Although I think I might not be satisfied with them
and write a class for logging on my own. Or is this
not recommended?Only if you can do a better job than has already been done, which you probably can't, and can afford the time to do so, which depends on whose time it is. Almost always not worth the bother. Logging APIs provide a means to write extensions, for instance Log4J provides the Appender API for you to write custom outputters, but the logging code itself remains the same. Look into Log4J and Java logging. Apache commons-logging might be of additional interest, too
I read somewhere that some logging classes do flush
output at different points so I am not sure if I can
rely on them - especially important when I run into
an infinite loop. If then the output from before
hasn't been flushed I will never find the real
position in code where the problem occurs.Yeh you will - the stack trace won't lie
When I cannot rely on the output (especially if the
output is not in the correct order) then it is a real
problem when examining log text (generally spoken).Not really. See above