how to replace a letter at specific place in a string java code example

Example 1: java replace character in string

String s = "new String";
String replaced = s.replace("new","Test");
							  ^		 ^
                             old    new char

Example 2: replace character in string java

String str = ".............................."; 

        int index = 5; 
  
        char ch = '|'; 
 
        StringBuilder string = new StringBuilder(str); 
        string.setCharAt(index, ch); 

        System.out.println(string);