{"id":868,"date":"2010-06-28T22:17:45","date_gmt":"2010-06-28T20:17:45","guid":{"rendered":"http:\/\/raftaman.net\/?p=868"},"modified":"2021-05-15T11:46:40","modified_gmt":"2021-05-15T09:46:40","slug":"duplicate-log4j-output-lines","status":"publish","type":"post","link":"https:\/\/possiblelossofprecision.net\/?p=868","title":{"rendered":"Duplicate log4j output lines"},"content":{"rendered":"<p>Ever seen duplicate lines in your log4j output? Maybe something like this:<\/p>\n<pre class=\"brush: plain; title: ; wrap-lines: false; notranslate\" title=\"\">\r\n2010-06-28 21:56:11,743 &#x5B;main] INFO  org.quartz.impl.StdSchedulerFactory - Quartz scheduler version: 1.8.1\r\n2010-06-28 21:56:11,743 &#x5B;main] INFO  org.quartz.impl.StdSchedulerFactory - Quartz scheduler version: 1.8.1\r\n2010-06-28 21:56:11,750 &#x5B;main] INFO  org.quartz.core.QuartzScheduler - Scheduler MyScheduler_$_1 started.\r\n2010-06-28 21:56:11,750 &#x5B;main] INFO  org.quartz.core.QuartzScheduler - Scheduler MyScheduler_$_1 started.\r\n<\/pre>\n<p>Well, the obvious cause is probably duplicate loggers your log4j configuration:<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\nlog4j.rootLogger=INFO, DefaultConsoleAppender\r\nlog4j.logger.org.quartz=DEBUG, DefaultConsoleAppender\r\n<\/pre>\n<p>As the properties are inherited from the root logger, this is telling log4j that all <code>quartz<\/code>-classes should send their log to the <code>DefaultConsoleAppender<\/code> (which the root logger is doing anyway). So we simply have to remove the appender from the second logger definition:<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\nlog4j.rootLogger=INFO, DefaultConsoleAppender\r\nlog4j.logger.org.quartz=DEBUG\r\n<\/pre>\n<p>So watch your <strong>inherited log levels and appenders<\/strong> in your log4j configuration!<\/p>\n<p>If anyone knows, why these duplicate lines appear from time to time in <strong>heavily multi-threaded environments<\/strong> (although log4j <a title=\"Log4j FAQ\" href=\"http:\/\/logging.apache.org\/log4j\/1.2\/faq.html#a1.7\">claims to be thread-safe<\/a>) despite correct property files, please drop me a mail or leave a comment.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ever seen duplicate lines in your log4j output? Maybe something like this: 2010-06-28 21:56:11,743 &#x5B;main] INFO org.quartz.impl.StdSchedulerFactory &#8211; Quartz scheduler version: 1.8.1 2010-06-28 21:56:11,743 &#x5B;main] INFO org.quartz.impl.StdSchedulerFactory &#8211; Quartz scheduler version: 1.8.1 2010-06-28 21:56:11,750 &#x5B;main] INFO org.quartz.core.QuartzScheduler &#8211; Scheduler MyScheduler_$_1 started. 2010-06-28 21:56:11,750 &#x5B;main] INFO org.quartz.core.QuartzScheduler &#8211; Scheduler MyScheduler_$_1 started. Well, the obvious cause is probably duplicate loggers your log4j&#8230; <a href=\"https:\/\/possiblelossofprecision.net\/?p=868\">Read more &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[4,33],"class_list":["post-868","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-java","tag-log4j"],"_links":{"self":[{"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/posts\/868","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=868"}],"version-history":[{"count":8,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/posts\/868\/revisions"}],"predecessor-version":[{"id":877,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=\/wp\/v2\/posts\/868\/revisions\/877"}],"wp:attachment":[{"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=868"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=868"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/possiblelossofprecision.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=868"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}