public class StringBufferDemo {
       public static void main(String [] args){
               StringBuffer buffer = new StringBuffer(20);
               buffer.append('S');
               buffer.append("tringBuffer");
        //     System.out.println(buffer.charAt(1));
               System.out.println(buffer.capacity());
        //     System.out.println(buffer.indexOf("tring12345"));
               System.out.println("buffer = " + buffer.toString());
               System.out.println(buffer.length());
          }
}