string.java

public class string {

    public static void main(String[] args) {
        final int NN = 40000;
        final int N =  20000000;

        long t;

        {
            t = System.currentTimeMillis();
            String s = new String();
            for (int i = NN; i-- > 0 ;) {
                s += "s";
            }
            System.out.println(System.currentTimeMillis() - t);
        }

        {
            t = System.currentTimeMillis();
            StringBuffer sb = new StringBuffer();
            for (int i = N; i-- > 0 ;) {
                sb.append("s");
            }
            System.out.println(System.currentTimeMillis() - t);
        }

        {
            t = System.currentTimeMillis();
            StringBuilder sb = new StringBuilder();
            for (int i = N; i-- > 0 ;) {
                sb.append("s");
            }
            System.out.println(System.currentTimeMillis() - t);
        }

    }

}