Java Stringbuilder class
Strings in java are immutable (not editable)
so to make changes in string we use this string builder class which makes the string mutable (editable)
- This method will simply append an string to existing string.
- this will insert an character or strig at given position in given string.
this will replace certain part of string with another string.
it take position of string which need to be replaced.
- this method will delete certain part of string by taking starting and ending position.