[JELLY-235] nested exceptions are displayed incorrectly with JellyException

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.0
• Component/s: core / taglib.core
• Assignee: Unassigned
• Reporter: Kohsuke Kawaguchi
• Created: 06/Aug/06 16:19
• Updated: 05/Sep/09 10:03

Description

JellyException has some built-in support for nested exceptions. In particular, when it displays a stack trace, it tries to also displays the nested exception, which is great.

What's not so great is that when JDK 1.4 added this on its own, both Jelly and JDK try to display the nested exceptions, and you ended up seeing O(n^2) stack traces for n-level nested exception.

Imagine a situation where N JellyExceptions are nested inside each other.
With the following current printStackTrace:

    public void printStackTrace() {
        super.printStackTrace();
        if (cause != null) {
            System.out.println("Root cause");
            cause.printStackTrace();
        }
    }

Outer JellyException prints its stack trace first (in which JDK prints out all the nested exceptions),
and then JellyException prints the stack trace of the inner JellyException. Then this same step is repeatedly, causing an output like this:

JellyExpception 3
Caused by JellyException 2
Caused by JellyException 1
Root cause:
JellyException 2
Caused by JellyException 1
Root cause:
JellyException 1

See the attached patch for one possible fix.

Personally, I don't mind if JellyException choose to completely stop trying to print out the nested exception on its own, and simply delegate everything to JDK. This will make the output worse on JDK 1.3 and earlier, but the # of people using those is shrinking every day.

Issue Links

• is related to: JELLY-146 jelly should avoid java exceptions