I'm using the MemoryDataStore in projects and a client application pushes Features with the FeatureWriter to the DataStore. A layer based on the FeatureType of the DataStore shows the features.
a ConcurrentModificationException is thrown within the StreamingRenderer while the applictaion is still writing features.
To simulate this effect a test-class is attached. And also a patch for the MemoryDataStore-class. I guess the org.geotools.gui.swing.map.map2d.stream.TempMemoryDataStore class was created to solve this problem, but it doesn't.