In case of an error, they key is removed from the output.

Example:

1. Enable Web Fetchers
2. Select "Springer"
3. Search for "anything"

You will get

The output looks a bit strange as one would expect that only the key is not shown - and thus, the URL makes the impression of being invalid

Task

1. Modify the constant to have a regex group for the API key:

   jabref/jablib/src/main/java/org/jabref/logic/importer/FetcherException.java

   Line 17 in 1aae72d

   private static final Pattern API_KEY_PATTERN = Pattern.compile("(?i)(api|key|api[-_]?key)=[^&]*");

   . Use a "named group" for readability.
2. Modify getRedactedUrl (

   jabref/jablib/src/main/java/org/jabref/logic/importer/FetcherException.java

   Line 89 in 1aae72d

   return API_KEY_PATTERN.matcher(url).replaceAll(REDACTED_STRING);

   ) to replace only the group of the key - and not all.
3. Make the method returning String instead of Object.
4. Make the method package private and add @VisibleForTesting
5. Add test cases - using @ParameterizedTest and @CsvSource. Hint: Use Ctrl+Shift+T to create a test class.

To increase debugging - the first letter of the API key could still be output - please modify the regex accordingly.

Benefits

Learn how regular expressions work in Java