public class StringBuffTest {
   public static void main(String argv[]) {
        String s = null;
        StringBuffer sb = new StringBuffer();
        Runtime rt = Runtime.getRuntime();
        long startMemory = 0;
        long startTime = 0;
        startMemory = rt.freeMemory();
        startTime = System.currentTimeMillis();
        for (int i = 0; i < 10000; i++) {
            sb.append("HelloThere");
        }

        long endMemory = rt.freeMemory();
        long endTime = System.currentTimeMillis();

        System.out.println("Elapsed time: " + (endTime - startTime) + " ms");
        System.out.println("Memory usage: " + (startMemory - endMemory) + " bytes");
   }
}