public boolean addAll(Collection c){
  Object[] a=c.toArray();
  int numNew=a.length;
  ensureCapacity(size + numNew);
  System.arraycopy(a,0,elementData,size,numNew);
  size+=numNew;
  return numNew != 0;
}

public boolean addAll ( Collection c ) { Object [ ] a = c . toArray ( ) ; int numNew = a . length ; ensureCapacity ( size + numNew ) ; System . arraycopy ( a , 0 , elementData , size , numNew ) ; size += numNew ; return numNew != 0 ; }
appends all of the elements in the specified collection to the end of this list , in the order that they are returned by the specified collection ' s iterator . the behavior of this operation is undefined if the specified collection is modified while the operation is in progress . ( this implies that the behavior of this call is undefined if the specified collection is this list , and this list is nonempty . )
