How to i mask all string characters except for the last 4 characters in Java using parameters?

Question

i will like to know how do i mask any number of string characters except the last 4 strings. I want to masked all strings using "X"

For example

Number:"S1234567B"

Result

Number :"XXXXX567B

Thank you guys

Answer 1

You can do it with the help of StringBuilder in java as follows,

String value = "S1234567B";
String formattedString = new StringBuilder(value)
    .replace(0, value.length() - 4, new String(new char[value.length() - 4]).replace("\0", "x")).toString();
System.out.println(formattedString);