public CharBuffer(int capacity){
  if (capacity < 0)   throw new IllegalArgumentException();
  capacity=Math.max(capacity,MIN_CAPACITY);
  init(new char[capacity],0,0);
}

public CharBuffer ( int capacity ) { if ( capacity < 0 ) throw new IllegalArgumentException ( ) ; capacity = Math . max ( capacity , MIN_CAPACITY ) ; init ( new char [ capacity ] , 0 , 0 ) ; }
constructs a char buffer with the given initial capacity
