添加本地源
cd /etc/yum.repos.d/
vi localyum.repo
内容为：
[BaseOS]
name=BaseOS
baseurl=file:///run/media/root/RHEL-8-3-0-BaseOS-x86_64/BaseOS
enabled=1
gpgcheck=0
[AppStream]
name=AppStream
baseurl=file:///run/media/root/RHEL-8-3-0-BaseOS-x86_64/AppStream
enabled=1
gpgcheck=0
再执行以下命令：
yum makecache
yum repolist
yum install java-1.8.0-openjdk-headless.x86_64*