Comparison of 4 ways to concat Strings

ConcatStringComparison.java

package com.fewlaps;

public class ConcatStringComparison {

    static long timeAdding;
    static long timeConcat;
    static long timeStringBuffer;
    static long timeStringBuilder;

    public static final int ITERATIONS = 1000000;

    public static void main(String[] args) {

        long now = System.currentTimeMillis();
        String something = "";
        for (int i = 0; i < ITERATIONS; i++) {
            something = something + "a";
        }
        timeAdding = System.currentTimeMillis() - now;

        now = System.currentTimeMillis();
        something = "";
        for (int i = 0; i < ITERATIONS; i++) {
            something = something.concat("a");
        }
        timeConcat = System.currentTimeMillis() - now;

        now = System.currentTimeMillis();
        StringBuffer sbuffer = new StringBuffer();
        for (int i = 0; i < ITERATIONS; i++) {
            sbuffer.append("a");
        }
        timeStringBuffer = System.currentTimeMillis() - now;

        now = System.currentTimeMillis();
        StringBuilder sbuilder = new StringBuilder();
        for (int i = 0; i < ITERATIONS; i++) {
            sbuilder.append("a");
        }
        timeStringBuilder = System.currentTimeMillis() - now;


        System.out.println("Adding: " + timeAdding);
        System.out.println("Concat: " + timeConcat);
        System.out.println("Buffer: " + timeStringBuffer);
        System.out.println("Builder: " + timeStringBuilder);
    }
}

The result in my machine:

Adding: 257541
Concat: 178832
Buffer: 20
Builder: 14