/*

* This example shows that StringBuilder may be faster than String in

* certain circumstances. Since you cannot change a String object, you

* should consider using StringBuilder in cases when you want to change

* the String.

*

* The sample below changes the "helloX" to "hello!". The first method uses String.

* The second method uses StringBuilder. This operation is repeated millions of times

* and the elapsed time is displayed. Note how much faster StringBuilder is.

*/

public class StringExample {

public static void main(String[] args) {

String s = "helloX";

StringBuilder sb = new StringBuilder("helloX");

long start, end;

int reps = 50000000;

/** use String to change the character X to the character ! */

start = System.currentTimeMillis();

for (int i=0; i < reps; i++) {

s = s.substring(0,5) + "!";

}

end = System.currentTimeMillis();

System.out.println("With String, the elapsed time in seconds is " + ((float)(end-start)/1000));

/** use StringBuilder to change the character X to the character ! */

start = System.currentTimeMillis();

for (int i=0; i < reps; i++) {

sb.setCharAt(5, '!');

}

end = System.currentTimeMillis();

System.out.println("With StringBuilder, the elapsed time in seconds is " + ((float)(end-start)/1000));

}

}