code: private static FieldType getPlaceholder(final Class<?> type, final int fieldID)
     {
        return new FieldType()
        {
           @Override public FieldTypeClass getFieldTypeClass()
           {
              return FieldTypeClass.UNKNOWN;
           }
  
           @Override public String name()
           {
              return "UNKNOWN";
           }
  
           @Override public int getValue()
           {
              return fieldID;
           }
  
           @Override public String getName()
           {
              return "Unknown " + (type == null ? "" : type.getSimpleName() + "(" + fieldID + ")");
           }
  
           @Override public String getName(Locale locale)
           {
              return getName();
           }
  
           @Override public DataType getDataType()
           {
              return null;
           }
  
           @Override public FieldType getUnitsType()
           {
              return null;
           }
  
           @Override public String toString()
           {
              return getName();
           }
        };
     }
docs: Generate a placeholder for an unknown type.
  
  @param type expected type
  @param fieldID field ID
  @return placeholder