Regex to match ampersand between two single-letter words

I want to replace ampersand when it is found between two single-letter words.

Given below is the regex I use, but it is matching words consisting or two or more letters, too.

([A-Za-z]{1})((\s&\s)|(&)|(\s&)|(&\s))([A-Za-z]{1})

On top of that, there might be spaces between either of the letters.

E.g.:

1. A &B Should be replaced as AB
2. A& B Should be replaced as AB
3. A&B Should be replace as AB
4. ALPHA & B should not be matched. (Since ALPHA is a word)
5. ALPHA & BETA Should not be matched. (Since ALPHA & BETA both are words)

You may use

String result = s.replaceAll("(\\b[A-Za-z])\\s*&\\s*(?=[A-Za-z]\\b)", "$1")

Note: [A-Za-z] may be replaced with \\p{Alpha} (to match any ASCII letter) or \\p{L}) (to match any Unicode letter).

See the regex demo. Details

• (\b[A-Za-z]) - Group 1: a word boundary and a letter
• \s*&\s* - a & enclosed with 0 or more whitespace chars
• (?=[A-Za-z]\b) - a positive lookahead (to allow overlapping matche) that requires a letter followed with a word boundary immediately to the right of the current location.

To keep the first one-letter word in the result, the replacement pattern contains $1 placeholder.