[LOG4J2-726] logging hang when PatternLayout's pattern has miss pattern

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 2.0.2
• Component/s: Configurators

Environment

windows 8.1 64bit
java 1.7.0_55 64bit
log4j2 2.0

• Assignee: Remko Popma
• Reporter: moonumi
• Created: 20/Jul/14 23:54
• Updated: 22/Aug/14 02:37
• Resolved: 10/Aug/14 08:34

Description

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
    <Logger name="com.foo.Bar" level="trace" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Root level="error">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

The above configuration syntax is correct. However, if one makes a mistake and instead writes:

<PatternLayout pattern="%d\{HH:mm:ss.SSS  [%t] %-5level %logger\{36\} - %msg%n"/>

Note the ommited character "}" in the date pattern.

Run sample application.
This will hang log4j2 logging system.

sample source code:

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
 
public class HelloWorld {
    private static Logger logger = LogManager.getLogger("HelloWorld");
    public static void main(String[] args) {
        logger.info("Hello, World!");
    }
}

appear pattern configuration error or logging print miss pattern.