JAVA_HOME not found when following the install directions?

CentOS 6.10 (latest)
ES 7.3 (latest)

I'm using the link below to perform an rpm install:
https://www.elastic.co/guide/en/elasticsearch/reference/current/rpm.html#rpm

I followed the steps above, and tried to start elasticsearch:
**sudo -i service elasticsearch start

which: no java in (/sbin:/usr/sbin:/bin:/usr/bin)

Could not find any executable java binary. Please install java in your PATH or set JAVA_HOME**

I read that java was included in the install...is it not? Pardon my frustration but its off-putting that I can follow the direction verbatim, and not get the same results. Its not mentioned anywhere about installing java. Is there a version that comes with the rpm or no? IMO I shouldn't be stuck 5 minutes into the process when following official documentation.

There error message you are getting looks like it is from a much older version of elasticsearch. Can you please provide the exact steps you used to install Elasticsearch? Can you verify there is not an older version on the system?