log4j truncates stacktrace

Question

I'm having a problem printing the stacktrace to my log file. Log4j.properties:

log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=/var/log/app/application.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %c{1} [%p] %m%n

log4j.rootLogger=warn, file
log4j.logger.com.app=info, file
log4j.additivity.com.app=false

when I log an exception like this in my class UserGuard.java:

} catch (Exception e) {
    log.error("Uncaught error", e);
    response.setEntity(new StringRepresentation(" "));
    response.setStatus(Status.SERVER_ERROR_INTERNAL);
}

This results in my application.log :

2011-12-28 07:30:03 UserGuard [ERROR] Uncaught error
java.lang.NullPointerException

No stack trace shown. This is really annoying. Thanks!

Tried with same pom.xml and same log4j.properties on another machine and works ok. Should I think that the problem is my java version?

Does the problem still occur if you use a different appender, such as a ConsoleAppender? Have you tried running log4j with debug output enabled so you can see if there are any errors in your log4j config? — chrisbunney, Dec 28 '11 at 13:02
Did you check [-Dlog4j.debug](http://jaitechwriteups.blogspot.com/2006/07/know-how-log4j-tries-to-configure.html)? Another option is to unpack sources and use debugger. — Miserable Variable, Jan 03 '13 at 22:34

score 8 · Accepted Answer · edited May 23 '17 at 11:52

Your stack traces are most likely getting truncated due to an optimization in Hotspot. The optimization only builds the identical stacktrace a limited number of times, and then future instances of the exception from the same exact place don't build it.

You can either turn off this optimization using the -XX:-OmitStackTraceInFastThrow flag, or go back to earlier logs to find the first instance of this exception occuring (it's logged once, then optimized away later).

See this related StackOverflow question, and this one, and this blog post over here.

score 0 · Answer 2 · answered Dec 28 '11 at 13:05

0

There is an enhancement to log4j: http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/EnhancedPatternLayout.html

answered Dec 28 '11 at 13:05

Joop Eggen

107,315
7
83
138

Didn't find anything useful there – Gonzalo Dec 29 '11 at 13:47

log4j truncates stacktrace

2 Answers2