question: public void ensureCapacity ( int minimumCapacity ) { internal . ensureCapacity ( minimumCapacity ) ; }
target:  Ensures that the capacity of the buffer is at least equal to the specified minimum. If the current capacity of this string buffer is less than the argument, then a new internal buffer is allocated with greater capacity. The new capacity is the larger of: The minimumCapacity argument. Twice the old capacity, plus 2. If the minimumCapacity argument is nonpositive, this method takes no action and simply returns.