How to hide elements between < > characters in Java?

Question

Java

Please tell me how to write a method that would turn the information between < and > into ***
Input: Credit card number <4008 1234 5678> 8912
Output: Credit card number *** 8912
Regular expressions cannot be used. I'm trying like this:

public static String searchAndReplaceDiamonds(String text, String placeholder) {
        if (text.contains("<")) {
            if (text.contains(">")) {
                System.out.println(text + placeholder);
            }
        }return text;
    }