### Question:
RecordId implements Serializable { @Override public int hashCode() { return (pageId+"_"+tupleNum).hashCode(); } RecordId(PageId pid, int tupleNo); int tupleno(); PageId getPageId(); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void hCode() { assertEquals(hrid.hashCode(), hrid2.hashCode()); }