code: public static DatabaseFieldDescriptor getDatabaseFieldDescriptor(final Field field) {
          DatabaseFieldDescriptor databaseFieldDescriptor = fieldToDataBaseFieldDescriptorMap.get(field);
          if (databaseFieldDescriptor == null) {
  
              DatabaseField databaseField = field.getAnnotation(DatabaseField.class);
              if (databaseField != null) {
                  databaseFieldDescriptor = new DatabaseFieldDescriptor(databaseField);
              } else {
  
                  // do we have a column definition?
                  final Column column = field.getAnnotation(Column.class);
                  if (column != null) {
                      databaseFieldDescriptor = new DatabaseFieldDescriptor(column);
                  }
              }
  
              fieldToDataBaseFieldDescriptorMap.put(field, databaseFieldDescriptor);
          }
  
          return databaseFieldDescriptor;
      }
docs: get the database field annotation from a given field. This function will check against
  {@link javax.persistence.Column} definition so that both annotations can be used to mark a DatabaseField.
  
  @param   field  the field to be checked
  
  @return  a {@link de.zalando.typemapper.core.DatabaseFieldDescriptor} based on a found {@link DatabaseField} or
  {@link javax.persistence.Column}