private String getSystemField(String fieldName) {
        List<String> values = m_valueMap.get(fieldName);
        return values == null ? null : values.get(0);
    }
private String getSystemField ( String fieldName ) { List < String > values = m_valueMap . get ( fieldName ) ; return values == null ? null : values . get ( 0 ) ; }
Get the first value of the given field, or null if there is no value.