How to remove spaces before and after the comma in java

Question

I have an input mismatch error.

used regular expression ("//s*,//s*",",") but it doesn't work.

Answer 1

You should use \\ instead of //

String input = "a , b , c , d";
String output = input.replaceAll("\\s*,\\s*", ",");
System.out.println(output); // output: "a,b,c,d"