Migrating from Log4j 1 to Log4j 2

The logging framework in NexJ CRM has been upgraded from Log4j version 1 to Log4j version 2 in the 21.12.1.0 release. The syntax for configuring logging has changed, and the table below has been provided to assist with your transition. It is important to review each row item and apply the corresponding changes after upgrading.

Task	Log4j 1 syntax	Log4j 2 syntax
Setting the system property for the configuration file	Uses the following syntax: TEXT `log4j.configuration`	Instead, use the following syntax: TEXT `log4j.configurationFile`
Setting the root logger	Uses the following syntax: TEXT `log4j.rootLogger=INFO`	Instead, use the following syntax: TEXT `log4j.rootLogger.level=INFO`
Property substitution	Not applicable	If you have a system property called `log.location`, it can be used within the configuration. For example, you can use the following syntax: TEXT `log4j.appender.rolling.fileName=${sys:log.location}`
Automatic reconfiguration	When file reconfiguration was on or off in Log4j 1, it uses the following syntax: CODE `log4j.configuration.watched=true`	File reconfiguration in Log4j 2 is applied using the `monitorInterval` attribute, which is stored in seconds. The file is examined the next time a log event is evaluated and the `monitorInterval` period has elapsed. For example, you can set the interval to 60 seconds using the following syntax: TEXT `log4j.monitorInterval=60`
Setting a logger	Uses the following syntax: TEXT `log4j.logger.nexj.core.rpc=INFO` Also, supports the following syntax: TEXT `log4j.logger.nexj.core.container=WARN` TEXT `log4j.logger.nexj.core.rpc.Auditor=DEBUG`	Instead, use the following syntax: TEXT `log4j.logger.<unique name>.name = <fully qualified class name> log4j.logger.<unique name>.level = <level>` For example, use: TEXT `log4j.logger.nexj-core-rpc.name=nexj.core.rpc log4j.logger.nexj-core-rpc.level=INFO` `nexj-core-rpc` is considered a single token for Log4j 2. The unique name used here is only an example. The developer configuring the logger may choose unique names as appropriate for their purpose. Additional examples are provided below: TEXT `log4j.logger.nexj-core-container.name=nexj.core.container log4j.logger.nexj-core-container.level=WARN` TEXT `log4j.logger.nexj‑core‑rpc‑tomcat‑Auditor.name=nexj.core.rpc.Auditor log4j.logger.nexj-core-rpc-tomcat-Auditor.level=DEBUG`
Setting an appender	Uses the following syntax to add an appender to the root logger: TEXT `log4j.rootLogger=INFO, console` Uses the following syntax to define an appender: TEXT `log4j.appender.console=org.apache.log4j.ConsoleAppender log4j.appender.console.layout=org.apache.log4j.PatternLayout log4j.appender.console.layout.ConversionPattern=%d[%t]%‑5p%c‑%m%n`	To add an appender to the root logger, use the following syntax: TEXT `Log4j.rootLogger.appenderRef.stdout.ref=STDOUT` To define an appender, use the following syntax: TEXT `log4j.appender.console.type=Console log4j.appender.console.name=STDOUT log4j.appender.console.layout.type=PatternLayout log4j.appender.console.layout.pattern=%d[%t]%‑5p%c‑%m%n`
Setting a rolling file appender	Uses the following syntax to add an appender to the root logger (console appender is also added): TEXT `log4j.rootLogger=INFO,console,R` Uses the following syntax to define the type: TEXT `log4j.appender.R=org.apache.log4j.RollingFileAppender` Uses the following syntax to set the pattern: TEXT `log4j.appender.R.layout=org.apache.log4j.PatternLayout log4j.appender.R.layout.ConversionPattern=%d[%t]% 5p%c %m%n` Uses the following syntax to set the maximum file size for the log: TEXT `log4j.appender.R.MaxFileSize=256MB` Uses the following syntax to set the file location: TEXT `log4j.appender.R.File=e:\console.log` Uses the following syntax to set the maximum number of rollover files: TEXT `log4j.appender.R.MaxBackupIndex=5` Supports the following additional options: TEXT `log4j.appender.R.immediateFlush=true log4j.appender.R.Append=false`	To add an appender to the root logger, use the following syntax: TEXT `log4j.rootLogger.appenderRef.rolling.ref=RollingFile` To define a type (and also set the name), use the following syntax: TEXT `log4j.appender.rolling.type=RollingFile log4j.appender.rolling.name=RollingFile` To set a pattern, use the following syntax: TEXT `log4j.appender.rolling.layout.type=PatternLayout log4j.appender.rolling.layout.pattern=%d[%t]%‑5p%c‑%m%n` To set a max file size for the log, use the following syntax: If you are adding one or more policies, the first line must be added. TEXT `log4j.appender.rolling.policies.type=Policies log4j.appender.rolling.policies.size.type=SizeBasedTriggeringPolicy log4j.appender.rolling.policies.size.size=256MB` To set a file location, use the following syntax: `filePattern` is a new attribute, and it defines the look of the rollover file name. TEXT `log4j.appender.rolling.fileName=e:\console.log log4j.appender.rolling.filePattern=e:\%d.%i.log.gz` To set the max number of rollover files, use the following syntax: TEXT `log4j.appender.rolling.strategy.type=DefaultRolloverStrategy log4j.appender.rolling.strategy.max=5` Supports the following additional options: TEXT `log4j.appender.rolling.immediateFlush=true log4j.appender.rolling.append=false` The following code shows an example: TEXT log4j.rootLogger.appenderRef.rolling.ref=RollingFile log4j.appender.rolling.type=RollingFile log4j.appender.rolling.name=RollingFile log4j.appender.rolling.fileName=${sys:log.location} log4j.appender.rolling.filePattern=${sys:log.location}-%i.log.gz log4j.appender.rolling.layout.type=PatternLayout log4j.appender.rolling.layout.pattern="%d %-5p [%c] (%t:%x) %m%n" log4j.appender.rolling.policies.type=Policies log4j.appender.rolling.policies.size.type=SizeBasedTriggeringPolicy log4j.appender.rolling.policies.size.size=256MB log4j.appender.rolling.filter.threshold.type=ThresholdFilter log4j.appender.rolling.filter.threshold.level=ALL

The examples listed above include the “log4j.” prefix, which is used when you are setting system properties through VM arguments. When you are configuring properties using a properties file, you will need to omit this prefix to conform to the standard Log4j 2 syntax.

Additional references

For additional Log4j 2 information, see:

Configuration with properties - https://logging.apache.org/log4j/2.x/manual/configuration.html#Properties
Property substitution – https://logging.apache.org/log4j/2.x/manual/configuration.html#PropertySubstitution

Troubleshooting

The common error shown below is caused by Log4j 2 attempting to parse a Log4j 1 property (for example, log4j.logger.nexj.core.rpc=INFO). Log4j 2 expects a token “name” after nexj and is unable to find it.

CODE

Exception in thread "Thread-0" java.lang.ExceptionInInitializerError
...
Caused by: nexj.core.util.UncheckedException: err.logger.initFailed
...
Caused by: org.apache.logging.log4j.core.config.ConfigurationException: No name attribute provided for Logger nexj

Logging configuration issues can be evaluated in more detail through the logs by setting the log4j.debug=true property in the application environment file.