Standardized main memory representation methods (DOM) are quite inadequate to represent large XML Documents, both in terms of space (necessary amount of memory) and,consequently, in time: it easily happens that it is not possible to load large XML documents in main memory. In this paper, we present Virtual DOM, a Java package that provides an efficient representation technique for large XMLdocuments. It adopts a specifically designed virtual memory technique: memory blocks allocated to represent the document are swapped, when necessary, by skipping the operating system swapping mechanism; this way, the actual main memory needs are kept under control, the thrashing phenomenon is avoided even for large documents.