SimpleGraph<V, E> biConnected = (SimpleGraph<V, E>) new SimpleGraph<>( Object.class );
Graphs.addGraph( biConnected, full );
Graphs.addGraph( biConnected, contracted );
BiconnectivityInspector inspector = new BiconnectivityInspector( biConnected );
LinkedList<Set<V>> components = new LinkedList( inspector.getBiconnectedVertexComponents() );
if( components.isEmpty() )
throw new IllegalStateException( "no components" );
Set<V> vertices = new HashSet<>( contracted.vertexSet() );