How to change the logging level in an included library?

Question

In this case I'm using the oshi sysinfo library, and spring boot too.

I tried using a log4j2.xml file with the com.github.oshi logger set to INFO but it did not work in turning off the following DEBUG-level messages.

...
04:33:57.687 [Thread-3] DEBUG oshi.util.FileUtil - Reading file /sys/devices/system/cpu/cpu10/cpufreq/scaling_cur_freq
04:33:57.687 [Thread-3] DEBUG oshi.util.FileUtil - Reading file /sys/devices/system/cpu/cpu10/cpufreq/scaling_cur_freq
/sys/devices/system/cpu/cpu13/cpufreq/scaling_cur_freq
04:33:57.707 [Thread-3] DEBUG oshi.util.FileUtil - Reading file 
...

https://github.com/oshi/oshi

The following setting in log4j2.xml did not work:

  <category name="oshi">
    <priority value="OFF"/>
  </category>

  <Loggers>
    <!-- avoid duplicated logs with additivity=false -->
    <Logger name="oshi" level="info" additivity="false">
      <AppenderRef ref="LogToRollingFile"/>
    </Logger>
    <Root level="info">
      <AppenderRef ref="LogToConsole"/>
    </Root>
  </Loggers>

pom.xml contains:

...
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-slf4j-impl</artifactId>
    </dependency>
...

Answer 1

It was a silly question.

I did set the log4j2.xml config, but that was ineffective because I had included a spring starter that included logback. So the slf4j-over-logback config was in effect. The Oshi library uses slf4j.

So I excluded the spring-boot-starter-logging jar and included the spring log4j2 starter as follows, and the problem went away:

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
      <exclusions>
        <exclusion>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-log4j2</artifactId>
      <version>2.5.4</version>
    </dependency>

The log4j2 config is now in effect via the slf4j-log4j bridge jars.