code: @Test public void testFurniture(){
    Chair chair=new Chair();
    chair.setId(1);
    chair.setMaterial("wood");
    chair.setColor("brown");
    chair.setArms(true);
    chair.setRecliner(false);
    entityMgr.persist(chair);
    Couch couch=new Couch();
    couch.setId(2);
    couch.setMaterial("wood");
    couch.setColor("brown");
    couch.setFoldOutBed(false);
    couch.setNumCushions(3);
    entityMgr.persist(couch);
    Table table=new Table();
    table.setId(3);
    table.setMaterial("formica");
    table.setColor("blue");
    table.setExtendable(true);
    table.setShape("circle");
    entityMgr.persist(table);
    Desk desk=new Desk();
    desk.setId(4);
    desk.setMaterial("pressBoard");
    desk.setColor("black");
    desk.setExtendable(false);
    desk.setShape("rectangle");
    desk.setNumDrawers(2);
    entityMgr.persist(desk);
    Furniture f1=entityMgr.find(Furniture.class,1);
    Furniture f2=entityMgr.find(Furniture.class,2);
    Furniture f3=entityMgr.find(Furniture.class,3);
    Furniture f4=entityMgr.find(Furniture.class,4);
    assertEquals(Chair.class,f1.getClass());
    assertEquals(Couch.class,f2.getClass());
    assertEquals(Table.class,f3.getClass());
    assertEquals(Desk.class,f4.getClass());
  }
  