Re: catching exceptions in a catch block

From:

"Mike Schilling" <mscottschilling@hotmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 8 Jun 2009 23:44:37 -0700

Message-ID:

<qxnXl.25523$as4.23962@nlpi069.nbdc.sbc.com>

crazy fo sheezy wrote:

Hi. I have this piece of code here:

try {
...
} catch (Exception e) {
PrintWriter pw = new PrintWriter(new BufferedWriter(new
FileWriter("c:\ \foo.log")));
e.printStackTrace(pw);
pw.close();
}

The problem I'm having is that the code in the catch block could
throw
an IOException, FileNotFound for example. I want to be able to log
all errors in a log file. So, my first thought was to try to wrap
everything in the catch block within its own try/catch. But then,
since I want to log all errors to a log file, I'll need to
instantiate
another PrintWriter in the second catch block (see below). If I
keep
going, then I just end up with a bunch nested try/catches with no
end
in sight.

You have to accept that you can't easily log errors caused by being
unable to write to the log file. Given this, you can write a logging
class:

    public class Log
    {
            private String logFile;

            public void logException(Exception ex)
            {
                   try
                   {
                         PrintWriter pw = new PrintWriter(new
BufferedWriter(new FileWriter(logFile));
                         e.printStackTrace(pw);
                        pw.close();
                    }
                    catch (Exception ex)
                    {
                        ; // what can you do?
                    }
                }
        }

and use this class to do all your logging. if you decide to, say,
have another file that collects all first-level logging errors, append
to it in the catch block (and ingore errors writing to it.) What
might work even better is to use a logging framework that handles all
of this for you, say java.util.logging.