java - Find and replace all NewLine or BreakLine characters with in a String - Platform independent

Question

I am looking for a proper and robust way to find and replace all newline or breakline chars from a String independent of any OS platform with .

This is what I tried, but didn't really work well.

public static String replaceNewLineChar(String str) {
    try {
        if (!str.isEmpty()) {
            return str.replaceAll("

", "\n")
                    .replaceAll("
", "\n")
                    .replaceAll(System.lineSeparator(), "\n");
        }
        return str;
    } catch (Exception e) {
        // Log this exception
        return str;
    }
}

Example:

Input String:

This is a String
and all newline chars 
should be replaced in this example.

Expected Output String:

This is a String
and all newline chars
should be replaced in this example.

However, it returned the same input String back. Like it placed and interpreted it as Newline again. Please note, if you wonder why would someone want in there, this is a special requirement by user to place the String in XML afterwords.

Answer 1

If you want literal then following should work:

String repl = str.replaceAll("(\r|\n|\r\n)+", "\\n")