code: public List<Node> getNodes(Collection<Long> nodeIds)
  	{
  		if(nodeIds.isEmpty()) return Collections.emptyList();
  		return getSomeElements(NODE + "s?" + NODE + "s=" + toCommaList(nodeIds), Node.class);
  	}
docs: Note that if not logged in, the Changeset for each returned element will be null
  
  @param nodeIds a collection of node ids to return.
  @throws OsmNotFoundException if <b>any</b> one of the given nodes does not exist
  @return a list of nodes.