in src/main/java/com/googlesource/gerrit/plugins/javamelody/GerritMonitoringFilter.java [191:195]
private boolean isPropertyUndefined(FilterConfig config, String name, String globalName) {
return System.getProperty(globalName) == null
&& config.getServletContext().getInitParameter(globalName) == null
&& config.getInitParameter(name) == null;
}