Android - print full exception backtrace to log

Question

I have a try/catch block that throws an exception and I would like to see information about the exception in the Android device log.

I read the log of the mobile device with this command from my development computer:

/home/dan/android-sdk-linux_x86/tools/adb shell logcat

I tried this first:

try {
    // code buggy code
} catch (Exception e)
{
    e.printStackTrace();
}

but that doesn't print anything to the log. That's a pity because it would have helped a lot.

The best I have achieved is:

try {
    // code buggy code
} catch (Exception e)
{
    Log.e("MYAPP", "exception: " + e.getMessage());             
    Log.e("MYAPP", "exception: " + e.toString());
}

Better than nothing but not very satisfying.

Do you know how to print the full backtrace to the log?

Thanks.

score 177 · Accepted Answer · edited Jul 15 '19 at 23:12

177

try {
    // code that might throw an exception
} catch (Exception e) {
    Log.e("MYAPP", "exception", e);
}

More Explicitly with Further Info

(Since this is the oldest question about this.)

The three-argument Android log methods will print the stack trace for an Exception that is provided as the third parameter. For example

Log.d(String tag, String msg, Throwable tr)

where tr is the Exception.

According to this comment those Log methods "use the getStackTraceString() method ... behind the scenes" to do that.

edited Jul 15 '19 at 23:12

TT--

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answered Dec 03 '10 at 00:23

EboMike

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In addition, My style: Log.e(e.getClass().getName(), e.getMessage(), e); – Vikas Jan 20 '11 at 09:54
29

Beware using e.getMessage() - getMessage() may return null, depending upon the type of exception that has been thrown, which would in itself cause an exception as null is not supported as a message parameter in the Log methods. See [here](http://developer.android.com/reference/java/lang/Throwable.html#getMessage%28%29) – Uniqe Jun 08 '11 at 09:52
1

Besides, it makes more sense to describe what kind of code caused this exception in the second parameter. The message is already included in the output anyway. – EboMike Mar 16 '14 at 00:40
1

What @Unique says is very important. It is better to use Log as mentioned in the answer since it already prints the stack trace – Buddy Sep 27 '15 at 18:42
`Log.e("MYAPP", "exception", e);` In this MYAPP is for what? Please explain – Abdulla Sirajudeen Jun 21 '16 at 03:36
1

@SignoffTeamz You could just read the documentation. It's an identifier that shows up the log that makes it easier for you to filter the log and see which app (and which part of it) wrote the message. https://developer.android.com/reference/android/util/Log.html#e(java.lang.String, java.lang.String, java.lang.Throwable) – EboMike Jun 21 '16 at 14:53

score 56 · Answer 2 · answered Sep 29 '11 at 15:44

56

This helper function also works nice since Exception is also a Throwable.

    try{
        //bugtastic code here
    }
    catch (Exception e)
    {
         Log.e(TAG, "Exception: "+Log.getStackTraceString(e));
    }

answered Sep 29 '11 at 15:44

George

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It is a string used to specify the app and location. Any string will do there. – George Mar 11 '16 at 19:42

score 8 · Answer 3 · answered Dec 03 '10 at 00:28

catch (Exception e) {
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  PrintStream stream = new PrintStream( baos );
  e.printStackTrace(stream);
  stream.flush();
  Log.e("MYAPP", new String( baos.toByteArray() );
}

Or... ya know... what EboMike said.

score 4 · Answer 4 · answered Aug 10 '15 at 18:30

4

public String getStackTrace(Exception e){
  StringWriter sw = new StringWriter();
  PrintWriter pw = new PrintWriter(sw);
  e.printStackTrace(pw);
  return sw.toString();
}

answered Aug 10 '15 at 18:30

Varun Narisetty

165
9

score 2 · Answer 5 · answered Dec 03 '10 at 00:33

2

e.printStackTrace() prints it to me. I don't think you're running the logcat correctly. Don't run it in a shell, just run

/home/dan/android-sdk-linux_x86/tools/adb logcat

answered Dec 03 '10 at 00:33

Falmarri

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score 1 · Answer 6 · edited Jun 18 '17 at 10:26

1

try{
            ...
} catch (Exception e) {
     Log.e(e.getClass().getName(), e.getMessage(), e.getCause());
}

edited Jun 18 '17 at 10:26

amin

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answered Dec 18 '15 at 03:04

Frank Hou

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Arvin Chen · Answer 7 · 2022-08-08T03:58:20.790

1

if you want to print out stack trace without exception, you can create it by following command

(new Throwable()).printStackTrace();

edited Aug 08 '22 at 03:58

answered Aug 08 '22 at 03:56

Arvin Chen

11
2

score 1 · Answer 8 · answered Nov 20 '11 at 12:09

1

The standard output and error output are directed to /dev/null by default so it is all lost. If you want to log this output then you need to follow the instructions "Viewing stdout and stderr" shown here

answered Nov 20 '11 at 12:09

toc777

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score 0 · Answer 9 · answered Mar 09 '17 at 20:51

In the context of Android, I had to cast the Exception to a String:

try {
    url = new URL(REGISTRATION_PATH);
    urlConnection = (HttpURLConnection) url.openConnection();
} catch(MalformedURLException e) {
    Log.i("MALFORMED URL", String.valueOf(e));
} catch(IOException e) {
    Log.i("IOException", String.valueOf(e));
}

score 0 · Answer 10 · answered Nov 12 '20 at 13:51

KOTLIN SOLUTION:

You can make use of the helper function getStackTraceString() belonging to the android.util.Log class to print the entire error message on console.

Example:

try { 
 
   // your code here
    
} catch (e: Exception) {

     Log.e("TAG", "Exception occurred, stack trace: " + e.getStackTraceString());

}

score 0 · Answer 11 · answered Apr 19 '21 at 14:49

0

Kotlin extension. Returns the detailed description of this throwable with its stack trace.

e.stackTraceToString()

answered Apr 19 '21 at 14:49

Dan

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Android - print full exception backtrace to log

11 Answers11

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