string replace at index code example
Example 1: how to change single character of a string in java
String s1 = "This is a String";
String s2 = s1.substring(0, 8) + "o" + s1.substring(9);
System.out.println(s2);
Example 2: java string replace character at position
String str = in.nextLine();
char cr = in.next().charAt(0);
int index = in.nextInt();
str = str.substring(0, index) + cr + str.substring(index + 1);
Example 3: java replaceall single character
.replaceAll("(?<!\\S)[^ ](?!\\S)", " ").trim()