src/main/java/com/googlecode/fascinator/harvester/workflow/WorkflowHarvester.java
private void storeList(Properties props, Map<String, List<String>> details,
            String field) {
        Set<String> valueSet = new LinkedHashSet<String>();
        // merge with original property value if exists
        String currentValue = props.getProperty(field, "");
        if (!"".equals(currentValue)) {
            String[] currentList = currentValue.split(",");
            valueSet.addAll(Arrays.asList(currentList));
        }
        valueSet.addAll(details.get(field));
        String joinedList = StringUtils.join(valueSet, ",");
        props.setProperty(field, joinedList);
    }
private void storeList(Properties props, Map<String, List<String>> details,
            String field) {
        Set<String> valueSet = new LinkedHashSet<String>();
        // merge with original property value if exists
        String currentValue = props.getProperty(field, "");
        if (!"".equals(currentValue)) {
            String[] currentList = currentValue.split(",");
            valueSet.addAll(Arrays.asList(currentList));
        }
        valueSet.addAll(details.get(field));
        String joinedList = StringUtils.join(valueSet, ",");
        props.setProperty(field, joinedList);
    }
Take a list of strings from a Java Map, concatenate the values together
and store them in a Properties object using the Map's original key.

@param props : Properties object to store into
@param details : The full Java Map
@param field : The key to use in both objects