StringBuffer

The reversed String could be built up character by character in an array. Since arrays can be altered at any time, only one new object would be constructed. This is essentially the idea of the StringBuffer class.

A StringBuffer object holds a String of characters that can be changed by appending characters at the end and by inserting characters. However, unlike a char array, a StringBuffer comes with many methods convenient for character manipulation. A StringBuffer automatically grows in length as needed. Constructors for StringBuffer are:

StringBuffer constructors
public StringBuffer()	create an empty StringBuffer
public StringBuffer(int capacity)	create a StringBuffer with initial room for capacity characters
public StringBuffer(String st)	create a StringBuffer containing the characters from st