code: public synchronized String setPropertyFormat(String pKey, String pFormat) {
  
      // Insert format
      return StringUtil.valueOf(mFormats.put(pKey, pFormat));
    }
docs: Sets the format of a property. This value is used for formatting the
  value before it is stored as xml.
  
  @param pKey a key in this hashtable.
  @param pFormat a string representation of the format.
  
  @return the previous format for the specified key or null if it did not
  have one.