StringBuffer capacity

[Alvin chew]

hi, good day everyone here , i get confuse on the capacity of stringbuffer,

if my stringbuffer content is : a*b*c*d*e*

when i use capacity method to check the capacity of my stringbuffer, why is it so my capacity is 16 ?

thank you very much for help

for your info :

i using following code to get the stringbuffer

 
 public void setFieldName(String tempfieldname)
    {                
        String newfieldname = tempfieldname;
        fieldnamesb.append(newfieldname + "*");
    }

and have been call 5 times by parameter a,b,c,d,e

[Ernest Friedman-Hill]

A StringBuffer has an array member that it uses to hold the characters, and an int that tells how many of the array positions are actually valid. The rest of the array contains zeroes, or garbage. In general, the size of the array (the capacity) won't be equal to the number of characters in the StringBuffer (the size).

It's quite inefficient to try to keep the array exactly the right size; to do so, StringBuffer would have to allocate a new array every time you called append. By keeping some extra empty space, StringBuffer can only reallocate the array once in a while.