package com.baeldung.string; public class ReplaceCharacterInString { public String replaceCharSubstring(String str, char ch, int index) { String myString = str.substring(0, index) + ch + str.substring(index+1); return myString; } public String replaceCharStringBuilder(String str, char ch, int index) { StringBuilder myString = new StringBuilder(str); myString.setCharAt(index, ch); return myString.toString(); } public String replaceCharStringBuffer(String str, char ch, int index) { StringBuffer myString = new StringBuffer(str); myString.setCharAt(index, ch); return myString.toString(); } }