Compile errors...

I download ftp://iris.ssec.wisc.edu/pub/visad-2.0/visad_src-2.0.jar
and got these compile errors:

  javac java3d/*.java
  java3d/MouseBehaviorJ3D.java:51: class visad.java3d.MouseBehavior must be 
    an interface.
      implements MouseBehavior {
  java3d/DisplayApplet.java:50: Incompatible type for method. Explicit cast
    needed to convert javax.media.j3d.Canvas3D to visad.java3d.VisADCanvasJ3D.
      BranchGroup scene = renderer.createSceneGraph(universe.view, canvas);

etc.  I'm using JDK 1.2 beta and Java3D Alpha 3.  Any suggestions?