private static String toStringWordCharsOnly(Map<String, String> map) {
    if (map == null){
      return "null";
    }
    StringBuilder sb = new StringBuilder();
    boolean first = true;
    for (Map.Entry<String,String> e : map.entrySet()){
      if (!first){
        sb.append(',');
      }
      sb.append(toStringWordCharsOnly(e.getKey()));
      sb.append('=');
      sb.append(toStringWordCharsOnly(e.getValue()));
      first = false;
    }
    return sb.toString();
  }
Return alphanumeric(and '_') representation of a Map<String,String>
hcatalog/webhcat/java-client/src/main/java/org/apache/hive/hcatalog/api/repl/ReplicationUtils.java