Java not installed or JAVA_HOME environment variable not set

Error when Java is not installed or the path is not set.

If Java is not installed, or if OpsCenter cannot find JAVA_HOME, the following error might display:

/usr/share/datastax-agent/bin/datastax-agent: line 98:exec: -X: invalid option
 exec: usage:  exec [-cl ] [-a name ] [ command [arguments ... ]] [redirection ... ]
To correct this problem, install Java or set the JAVA_HOME variable:
export JAVA_HOME=<path_to_java>

Where <path_to_java> is the path to where Java is installed.