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Editorial Team
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Asked: 2026-05-15T20:02:50+00:00

I want to log only the first few lines of Exceptions in my program.

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I want to log only the first few lines of Exceptions in my program. I know, I can do something like this to print only the first 5 lines of a stacktrace:

Throwable e = ...;
StackTraceElement[] stack = e.getStackTrace();
int maxLines = (stack.length > 4) ? 5 : stack.length;
for (int n = 0; n < maxLines; n++) {
    System.err.println(stack[n].toString());
}

But I would rather use log4j (or slf4j over log4j to be more precise) for logging. Is there a way to tell log4j that it should only print the first 5 lines of a stacktrace?

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1 Answer

  1. Editorial Team

    You can use an EnhancedPatternLayout in log4j to format your stacktraces.

    See http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/EnhancedPatternLayout.html, specifically the section about the "throwable" pattern in the pattern table.

    Note that support for %throwable{n} is rather new and requires at least log4j 1.2.16 (which is the latest at time of writing)

    For tracking purposes, this is the ticket that dealt with its implementation:
    https://issues.apache.org/bugzilla/show_bug.cgi?id=48902

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