Use character wrapper to code a replace a letter in a string with a new letter keeping the original case

Question

Trying to figure out how to use character wrapping to mutate a string based on user input. If string is \'Bob loves to build building\' and user chooses to replace all letter B/

Answer 1

Your question is unclear (how 'b' becomes 'm' in Bob -> Tom?). However, to run case insensitive replace you should do something like this:

String text ="Bob loves to build building";
String b = "b";

Pattern p = Pattern.compile(b, Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(text);

String outText = m.replaceAll("T");