public class  LockTest {
 private static final int MAX = 20000000; // 20 million

 public static void main(String[] args) throws InterruptedException {
 // warm up the method cache
 for (int i = 0; i < MAX; i++) {
     concatBuffer("Josh", "James", "Duke");
     concatBuilder("Josh", "James", "Duke");
 }

 System.gc();
 Thread.sleep(1000);

 System.out.println("Starting test");
 long start = System.currentTimeMillis();
 for (int i = 0; i < MAX; i++) {
     concatBuffer("Josh", "James", "Duke");
 }
 long bufferCost = System.currentTimeMillis() - start;
 System.out.println("StringBuffer: " + bufferCost + " ms.");

 System.gc();
 Thread.sleep(1000);

 start = System.currentTimeMillis();
 for (int i = 0; i < MAX; i++) {
     concatBuilder("Josh", "James", "Duke");
 }
 long builderCost = System.currentTimeMillis() - start;
 System.out.println("StringBuilder: " + builderCost + " ms.");
 System.out.println("Thread safety overhead of StringBuffer: "
 + ((bufferCost * 10000 / (builderCost * 100)) - 100) + "%\n");

 }

 public static String concatBuffer(String s1, String s2, String s3) {
     StringBuffer sb = new StringBuffer();
     sb.append(s1);
     sb.append(s2);
     sb.append(s3);
     return sb.toString();
 }

 public static String concatBuilder(String s1, String s2, String s3) {
     StringBuilder sb = new StringBuilder();
     sb.append(s1);
     sb.append(s2);
     sb.append(s3);
     return sb.toString();
 }

}