In general it is safe to ignore this message in Energy Logserver. Although we are using elasticsearch database we do not recommend installing third party plugins, as they might not work/break the system.
Still, if you are looking for something specific, please feel free to send us question about functionality that you are looking for 🙂
If you want to fix that anyway and still want to use this elasticsearch binary, please follow below command to set JAVA HOME variable:
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-11.0.13.0.8-4.el8_5.x86_64/