@wroot, thanks for your message!
Sorry for not very family with Linux and the exact OS version is: centos-release-7-6.1810.2.el7.centos.x86_64.
Here is the backgroud about:
Beacuse Oracle JDK is not free anymore since Jan 2019, so the company decided to replace the Java from Oracle JDK to OpenJDK, Openfire(now running 64bit JRE bundled) is included.
For this, we need to uninstall the JRE bundled version and install no JRE bundled one, right? Before that, we have to install OpenJDK first and when those steps are done, we’ll check if the Openfire no JRE bundled with openJDK is still working.
BTW, I have tried openJDK 11 with Openfire 4.4.1.noarch before, still got the same error message I mentioned it. Java 8 is not necessary.
I just want to figure out what is the root case for “java >= 1:1.8.0 is needed by openfire-4.4.1-1.noarch” when installing Openfire or if I just misunderstanding about Openfire between the diff versions and then did the incorrect operations for my purpose.