static String retrievePropertyFile() {
    return System.getProperty(AGENT_PROPSFILE_PROPERTY_NAME, DEFAULT_PROPERTY_FILE);
  }
The <code>propertyFile</code> is the name of the property file that will be loaded on startup
of the Agent.
<p>
The file will be searched for, in order, in the following directories:
<ol>
<li>the current directory
<li>the home directory
<li>the class path
</ol>
Only the first file found will be used.
<p>
The default value of propertyFile is <code>"agent.properties"</code>. However if the
"gfAgentPropertyFile" system property is set then its value is the value of propertyFile. If
this value is a relative file system path then the above search is done. If its an absolute
file system path then that file must exist; no search for it is done.
geode-core/src/main/java/org/apache/geode/admin/jmx/internal/AgentConfigImpl.java