SpotBugs - SBSC_USE_STRINGBUFFER_CONCATENATION

Description

SBSC: Method AppletComponent.getValue(String) concatenates strings using + in a loop

The method seems to be building a String using concatenation in a loop. In each iteration, the String is converted to a StringBuffer/StringBuilder, appended to, and converted back to a String. This can lead to a cost quadratic in the number of iterations, as the growing string is recopied in each iteration.

使用loop連接字串時，是使用+，會造成不必要的物件轉換。

Solution

Better performance can be obtained by using a StringBuffer (or StringBuilder in Java 1.5) explicitly.

透過StringBuffer將字串連接起來，再轉回String即可。

Example

Before:

return a + b + c;

After:

StringBuffer sb = new StringBuffer();
sb.append(a);
sb.append(b);
sb.append(c);
return sb.toString();