java : Using printStackTrace in Production Environment

Question

I am going to deploy our Web Application under Production server. Is including printStackTrace under catch block in production environment acceptable? (becuase the logs under catch block doesn't help to know the exact cause for the error) So please tell me if is it aceptable to have printStackTrace under catch block?

For instance, I purposefully put an invalid port number and printStackTrace() gives me this information.

printStackTrace() :

java.lang.IllegalArgumentException: port out of range:80800
        at java.net.InetSocketAddress.<init>(InetSocketAddress.java:118)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:395)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:530)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:234)
        at sun.net.www.http.HttpClient.New(HttpClient.java:307)
        at sun.net.www.http.HttpClient.New(HttpClient.java:324)
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)
        at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1014)
        at com.tata.util.XmlClient.execute(HttpXmlClient.java:83)

Log style :

And where as the log gives this (I am using Apache commons logging mechanism for logging)

 Log.write("**EXCEPTION INSIDE execute " + e, Log.INFO);

06/Jan/2012 16:25:55   - main:http-8080-2 <> <60990020>**EXCEPTION INSIDE execute  java.lang.IllegalArgumentException: port out of range:80800

So please tell me if is it acceptable to have printStackTrace under catch block?

score 5 · Accepted Answer · answered Jan 06 '12 at 11:24

5

The log will show the stacktrace as well, but you're not using it correctlly. Try:

log.error(Object message, Throwable t);

When you do Log.write("**EXCEPTION INSIDE execute " + e, Log.INFO); the plus sign used as String concatenator will in fact call the toString() method on the e object, and append that to the "**EXCEPTION INSIDE execute " String, never getting a change to get to the exception object or it's stack trace.

http://commons.apache.org/logging/guide.html#Logging a Message

answered Jan 06 '12 at 11:24

Shivan Dragon

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Thanks , so should i use in this way for this code ?? catch(Exception e){log.error(Object message, Throwable e)}; – Jan 06 '12 at 11:27
Yep, use it like that, should be ok. Check and see how it looks in the log and it's what you need. Remember that you can always use the Log4j config to change the way your log messages are formatted: http://www.allapplabs.com/log4j/log4j_layouts.htm – Shivan Dragon Jan 06 '12 at 11:32

score 1 · Answer 2 · answered Jan 06 '12 at 11:25

1

Having a stacktrace in your life app is certainly bad.

Why don't you create a popup for your printStackTrace and display it if a certain debug flag is active (not sure how this is done in java).

Usually you let all exceptions bubble up to where you need to handle them. A conntection error might be an information you want to display in your app, so youhandle it in your front end (e.g. in a popup).

And Andrei Bodnarescu is right, fixing your logger does the trick as well.

answered Jan 06 '12 at 11:25

Pete

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Can you shed some light on why stack traces in logs of production app are bad? I do believe otherwise and in particular, you might not be able to reproduce certain bug on your dev enviroment and thus, be stuck with bizzare exception in production box without slightiest idea why it is happening. – Jacek Prucia Dec 09 '14 at 11:53
We think, the stacktrace should never be visible to the user, as it might reveal the inner workings of your application and can lead to a security risk. Of course you cannot allow exceptions to get lost. But rather than display it to the user and leave him to decide what to do with it, you should handle it internally and log it in a file or/and as we do it, send an exception email, possibly with further information to a special exception email box the developers check regularly. – Pete Dec 11 '14 at 06:07

score 0 · Answer 3 · answered Jan 06 '12 at 11:26

Well, doing it that way is a first approach to logging and surely it will help on solving problems when they show up. But you can improve that using logging libraries like log4j or commons logger, setting your application to use them and output extra data (DB queries, result of operations, etc.), so you will retrieve some things alongside the stacktrace, perhaps with a better format.

Also, having the container/web server log with traces often raises doubts in clients, while having a structured application log keeps them a li'l bit more calm. A matter of perception.

score 0 · Answer 4 · answered Jan 06 '12 at 11:33

0

Yes, it is acceptable to print stack traces for exceptions in production environments. You can still throw the exception upwards for handling if you want.

answered Jan 06 '12 at 11:33

David Newcomb

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java : Using printStackTrace in Production Environment

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