I'm getting an error running my flex app. Where is the jar that contains the following classes?

import com.lightstreamer.as_client.LSClient;
import com.lightstreamer.as_client.ConnectionInfo;
import com.lightstreamer.as_client.ConnectionPolicy;
import com.lightstreamer.as_client.VisualTable;
import com.lightstreamer.as_client.NonVisualTable;