Issue with Java Regex \b

Question

I tried \b (This means the last character of a word) in the Java Regexp, but this doesn't work.

String input = "aaa aaa";
Pattern pattern = Pattern.compile("(a\b)");
Matcher matcher = pattern.matcher(input);

while (matcher.find()) {
    System.out.println("Found this wiki word: " + matcher.group());
}

What in the problem?

Answer 1

In Java, "\b" is a back-space character (char 0x08), which when used in a regex will match a back-space literal.

You want the regex a\b, which in java is coded by escaping the back-slash, like this:

"a\\b"

btw, you are only partially correct about the meaning of regex \b - it actually means "word boundary" (either the start or end of a word).