The best way to move forward in order to use Jaegar is NOT TO USE JAEGAR CLIENT!
Jaegar has the ability to collect Zipkin spans:
https://www.jaegertracing.io/docs/1.8/getting-started/#migrating-from-zipkin
You should take advantage of this and use the below Sleuth+Zipkin dependency and exclude Jaegar agent jars in your spring boot app.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-sleuth-zipkin</artifactId>
</dependency>
The above will send Zipkin spans to http://localhost:9411 by default. You can override this in your Spring Boot app to point to your Jaegar server easily by overriding the zipkin base URL.
spring.zipkin.base-url=http://your-jaegar-server:9411
Sleuth will do all the heavy lifting and the default logging will log the span and traceIds.
In the log4j2.xml file, all you have to mention is
[%X]
You can find the sample code here:
https://github.com/anoophp777/spring-webflux-jaegar-log4j2