Question

I have been using String to do the following.

String x = "a";
String y = "b";
String z = y+""+x;
x = y;
y = z;

So the final values of x and y are b and ba. I tried to use StringBuffer.

StringBuffer x = new StringBuffer("a");
StringBuffer y = new StringBuffer("b");
StringBuffer z = new StringBuffer();
z = y+""+x;   //??? 

API provides append function but it doesn’t do what concatenation does. Is there a equivalent for concatenation in StringBuffer class?

Answer 1

Dont’ use StringBuffer unless you have to. Java 5.0 and later uses StringBuilder by default

As of release JDK 5, this class has been supplemented with an equivalent class designed for use by a single thread, StringBuilder. The StringBuilder class should generally be used in preference to this one, as it supports all of the same operations but it is faster, as it performs no synchronization.

StringBuilder x = new StringBuilder("a");
StringBuilder y = new StringBuilder("b");
StringBuilder z = new StringBuilder().append(x).append(y);