How to replace single backslash(\) to double backslash(\\) in java?

Question

I have this string in my Java code which is coming from a URL:

String str = "C:\Program Files\Text.txt";

And I want to replace it to make it somewhat like this

String str = "C:\\\Program Files\\\Text.txt";

But Java isn't accepting str and also I cannot manually make the single backslash as double backslash everytime because it's coming from an URL. The code is showing this error below:

error: illegal escape character

String str = "C:\Program Files\Text.txt";

I have already tried "replace" and "replaceAll" but the issue is, it is not accepting my input so obviously it is not compiling. All in all my question is how do I take this string as input, String str = "C:\Program Files\Text.txt";

public class Example {
    public static void main(String[] args) {
        String str = "C:\Program Files\Text.txt";
        str = str.replace("\", "\\");
        System.out.println(str);
    }
}

Answer 1

Backslash is an escape sequence character, You can read about it here . It needs to be prefixed with \ .You need to do this:

String str = "C:\\Program Files\\Text.txt";
str = str.replace("\\", "\\\\");