private void initFields() {
      tag_ = 0L;
      type_ = org.box2d.proto.Box2D.PbShapeType.CIRCLE;
      center_ = org.box2d.proto.Box2D.PbVec2.getDefaultInstance();
      radius_ = 0F;
      points_ = java.util.Collections.emptyList();
      normals_ = java.util.Collections.emptyList();
      centroid_ = org.box2d.proto.Box2D.PbVec2.getDefaultInstance();
    }