public IOContainer(Collection<? extends IOObject> objectCollection){
  ioObjects=new ArrayList<>(objectCollection.size());
  ioObjects.addAll(objectCollection);
}

public IOContainer ( Collection < ? extends IOObject > objectCollection ) { ioObjects = new ArrayList < > ( objectCollection . size ( ) ) ; ioObjects . addAll ( objectCollection ) ; }
creates a new iocontainer containing the contents of the collection which must contain only ioobjects .
