Doc: add sample command for installing openjdk
Guide</cite>.</p>
<note type="important">PL/Java requires a Java environment on each Greenplum Database host.
Ensure that the same Java environment is at the same location on all hosts: masters and
- segments.</note>
+ segments. For example, to install OpenJDK
+ 11:<codeblock>$ yum install -y java-11-openjdk</codeblock></note>
<p>To install and use PL/Java:</p>
<ol>
<li>Specify the Java version used by PL/Java. Set the environment variables
