// tied to the same TDB database performing read
// transactions concurrently. If another write transaction
// starts, the call of dataset.begin(WRITE) blocks until
// existing writer finishes.
dataset.begin(ReadWrite.WRITE) ;
try
{
GraphStore graphStore = GraphStoreFactory.create(dataset) ;
// Do a SPARQL Update.
String sparqlUpdateString = StrUtils.strjoinNL(