Java 1.8 is the current version and you probably use it on your personal computer. Although EMCLI says it will work on Java 1.6 and newer versions, if you install it using Java 1.8, you get an error when you try to setup or synchronize it with the Enterprise Manager Cloud Control OMS server. The reason is that Java 1.8 will use TLS 1.2 as default protocol for secure connections.
To fix the problem, you need to download and apply Patch 17555224 for FMW 18.104.22.168.0 version. You can learn more from My Oracle Support Doc ID 1930390.1.