CharMatcher.javaLetterOrDigit is deprecated in Guava 23.2 [1]. Replace it with: - regular expression for matching - combination of inRange for replacements Also replace String.format in log messages with Logger's own formatting, and replace one-liner methods with inline calls. [1] https://github.com/google/guava/releases/tag/v23.2 Change-Id: Icaf7504e7250beaa92b9c86ad592649bd6fafcba