How to replace and split file path in java

I am using below code to replace "\\in" with "\\". "\\in" is the folder name and it can be anything in general.

input "C:\\Users\\Ashish.Gupta\\Documents\\in\\output\\in"

Expected replacedPath = "C:\\Users\\Ashish.Gupta\\Documents\\output\\"

java public class Test1 { public static void main(String[] args) { String IN = "\in"; String SLASH = "\"; String path = "C:\Users\Ashish.Gupta\Documents\in\output\in"; String replacedPath = path.substring(0, path.length()) .replaceAll(IN, SLASH); System.out.println("replacedPath" + replacedPath); String[] batchIdPath = replacedPath.split(File.separator); System.out.println("batchIdPath : " + batchIdPath); } } Getting below ERROR:

lang-none Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal/unsupported escape sequence near index 1 \in ^ at java.base/java.util.regex.Pattern.error(Pattern.java:2028) at java.base/java.util.regex.Pattern.escape(Pattern.java:2608) at java.base/java.util.regex.Pattern.atom(Pattern.java:2286) at java.base/java.util.regex.Pattern.sequence(Pattern.java:2159) at java.base/java.util.regex.Pattern.expr(Pattern.java:2069) at java.base/java.util.regex.Pattern.compile(Pattern.java:1783) at java.base/java.util.regex.Pattern.(Pattern.java:1430) at java.base/java.util.regex.Pattern.compile(Pattern.java:1069) at java.base/java.lang.String.replaceAll(String.java:2939) at Test1.main(Test1.java:14)