Synchronization and multiple threads

[<adam.b.feldman AT rutgers.edu>]

Firstly, I should mention that I just started using GraphStream(1.1.1) and 
it's
great, thanks for the amazing set of libraries!

I started off working in a single thread, and then realized I needed 
threading,
so I attempted to convert my code to something capable of handling threading. 
I
now have a thread that is pulling data from a stream and adding it to the
graph.  When I started threading program, I attempted to use the
ConcurrentGraph mentioned in the FAQ
(http://graphstream-project.org/doc/FAQ/The-Graph-Class/What-are-the-Graph-implementations_1.0/),
but I keep getting a "The import
org.graphstream.graph.implementations.ConcurrentGraph cannot be resolved"
error.   I did however find Graphs.synchronizedGraph(g).  With this, nodes add
without error, but edges, I've been gettting:
"
Exception in thread "Thread-0" java.lang.ClassCastException:
org.graphstream.graph.implementations.Graphs$SynchronizedNode cannot be cast 
to
org.graphstream.graph.implementations.AbstractNode
        at
org.graphstream.graph.implementations.AbstractGraph.addEdge(AbstractGraph.java:334)
        at
org.graphstream.graph.implementations.AbstractGraph.addEdge(AbstractGraph.java:329)
        at
org.graphstream.graph.implementations.Graphs$SynchronizedGraph.addEdge(Graphs.java:423)
"

My code at the point of this error is:
e=g.addEdge(id, n1, n2);

Any suggestions on how to resolve these issues?  Thanks in advance.