[jboss-jira] [JBoss JIRA] (JGRP-1757) Logging: exceptions are not logged correctly

[Bela Ban (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12932828#comment-12932828 ] 

Bela Ban commented on JGRP-1757:
--------------------------------

The problem is that I used log.error/warn(String format, Throwable t) the wrong way:

Correct use:
{code:java}
catch(Throwable t) {
    log.error("there was a problem", t);
}
{code}

Incorrect use:
{code:java}
catch(Throwable t) {
   log.error("there was a problem: %s", t);
}
{code}

The format parameter %s is not needed.

If we call
{code:java}
log.error("%s: there was a problem", local_addr, t);
{code}
, then we'll use {{log.error(String format, Object ... args)}}, and t will be evaluated as an object and its toString() method will be called (no stack trace).
                
> Logging: exceptions are not logged correctly
> --------------------------------------------
>
>                 Key: JGRP-1757
>                 URL: https://issues.jboss.org/browse/JGRP-1757
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>            Priority: Minor
>             Fix For: 3.4.2, 3.5
>
>
> When calling
> {code:java}
> log.error("failure: %s", new NullPointerException("booom"));
> {code}, the stack trace of the exception is not shown immediately following the error string:
> {noformat}
> 704 [ERROR] jgroups: failure: %s
> java.lang.NullPointerException: booom
>         at org.jgroups.tests.bla4.main(bla4.java:14) [classes/:?]
> {noformat}
> Invoking {{toString()}} on the exception works, but in some cases, we want to be able to see the stack trace.
> Investigate how to show the stack trace on all (currently) 3 loggers (JDK, log4j and log4j2).

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