\s
is a shortcut for whitespace characters in regex. It has no meaning in a string. ==> You can’t use it in your replacement string. There you need to put exactly the character(s) that you want to insert. If this is a space just use " "
as replacement.
The other thing is: Why do you use 3 backslashes as escape sequence? Two are enough in Java. And you don’t need a |
(alternation operator) in a character class.
L.replaceAll("[\\t\\n\\r]+"," ");
Remark
L
is not changed. If you want to have a result you need to do
String result = L.replaceAll("[\\t\\n\\r]+"," ");
Test code:
String in = "This is my text.\n\nAnd here is a new line";
System.out.println(in);
String out = in.replaceAll("[\\t\\n\\r]+"," ");
System.out.println(out);