Java - Escaping Meta-characters [ and ] in Regex [duplicate]

Answer 1

Try \\[ and \\]. You need to double escape, because \ is also an escape character for strings (as is \" when you want to have double-quotes in your text). Therefore to get a \ in your string you have to use \\.

Answer 2

Regex patterns use \ as escape character, but so does Java. So to get a single escape (\) in a regex pattern you should write: \\. To escape an escape inside a regex, double the pattern: \\\\.

Of course that's extremely tedious, made all the worse because regexes have a ton of escape sequences like that. Which is why Java regexes also support “quoting” litteral parts of the pattern and this allows you to write your pattern as: \\Q[]\\E.

EDIT: As the other answer hints at: java.util.regex.Pattern.quote() performs this wrapping between \\Q and \\E.

Answer 3

aString.replaceFirst("\\[\\]", "blah");

or in the more general case

aString.replaceFirst(java.util.regex.Pattern.quote("[]"), "blah");