string buffer capacity

when i run this code the output is that the string buffer capacity is 17 and then after the for loop finishes it's capacity is 36. i know that the capacity changes as the object increases, but i was wondering why it's capacity starts off at 17 and ends at 36.

thanks

class StringBuffer{

static String dupl(String s,int times){

StringBuffer result =new StringBuffer(s);

System.out.println("result.capacity() = "+result.capacity());//17

for (int i=1; i<times; i++){

result.append(s);

}

System.out.println("result.capacity() = "+result.capacity());//36

return result.toString();

}

publicstaticvoid main(String[] args){

System.out.println(dupl("b",20));

}

}

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[1448 byte] By [mark_8206a] at [2007-11-27 11:17:34]