code: public static void setSpecificNamedOutputContext(Configuration conf, Job job, String namedOutput) {
  		for(Map.Entry<String, String> entries : conf) {
  			String confKey = entries.getKey();
  			String confValue = entries.getValue();
  			if(confKey.startsWith(MO_PREFIX + namedOutput + CONF)) {
  				// Specific context key, value found
  				String contextKey = confKey.substring((MO_PREFIX + namedOutput + CONF + ".").length(),
  				    confKey.length());
  				job.getConfiguration().set(contextKey, confValue);
  			}
  
  			if(confKey.startsWith(DEFAULT_MO_PREFIX + CONF)) {
  				// Default context applied to all named outputs
  				String contextKey = confKey.substring((DEFAULT_MO_PREFIX + CONF + ".").length(),
  				    confKey.length());
  				job.getConfiguration().set(contextKey, confValue);
  			}
  		}
  	}
docs: Iterates over the Configuration and sets the specific context found for the namedOutput in the Job instance.
  Package-access so it can be unit tested. The specific context is configured in method this.
  {@link #addNamedOutputContext(Job, String, String, String)}.
  
  @param conf
  The configuration that may contain specific context for the named output
  @param job
  The Job where we will set the specific context
  @param namedOutput
  The named output