Why is there a space at the beginning of each line of my Logback-generated log file?

Question

I'm using Logback for logging. At the beginning of each line after the first line is a space. Any idea why?

Below is my logback.xml:

<?xml version="1.0" encoding="utf-8"?>
<configuration debug="true">

  <property name="log.pattern" value="%d{yyyy/MM/dd HH:mm:ss.SSS} %-5level [%logger{0}] %msg%n %ex"/>

  <property name="log.file.prefix" value="${app.home}/var/log/${app.name}"/>

  <appender name="DEFAULT" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${log.file.prefix}.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
        <fileNamePattern>${log.file.prefix}.%d{yyyyMMdd}.%i.log.zip</fileNamePattern>
        <timeBasedFileNamingAndTriggeringPolicy
                class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
            <maxFileSize>500MB</maxFileSize>
        </timeBasedFileNamingAndTriggeringPolicy>
    </rollingPolicy>
    <encoder>
          <Pattern>${log.pattern}</Pattern>
    </encoder>
  </appender>

  <!-- info for everything else -->
  <root level="info">
    <appender-ref ref="DEFAULT"/>
  </root>
</configuration>

This results in log output like the following (notice the first line doesn't have a a space):

2012/02/06 13:34:09.875 INFO  [BrokerService] Using Persistence Adapter: MemoryPersistenceAdapter
 2012/02/06 13:34:09.875 INFO  [BrokerService] ActiveMQ 5.3.1 JMS Message Broker (localhost) is starting
 2012/02/06 13:34:09.875 INFO  [BrokerService] For help or more information please see: http://activemq.apache.org/
 2012/02/06 13:34:09.953 INFO  [ManagementContext] JMX consoles can connect to service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi
 2012/02/06 13:34:10.328 INFO  [BrokerService] ActiveMQ JMS Message Broker (localhost, ID:NZucker-NYL-3937-1328553250062-0:0) started
 2012/02/06 13:34:10.343 INFO  [TransportConnector] Connector vm://localhost Started

Answer 1

Change the value of log.pattern to

 "%d{yyyy/MM/dd HH:mm:ss.SSS} %-5level [%logger{0}] %msg%n%ex"

Note: there is no space between %n and %ex.