### Question:
DefaultOrdinalReferenceSystem extends DefaultTemporalReferenceSystem implements OrdinalReferenceSystem { @Override public boolean equals(Object object, ComparisonMode mode) { if (object == this) return true; final boolean sup = super.equals(object, mode); if (!sup) return false; if (object instanceof DefaultOrdinalReferenceSystem && super.equals(object)) { final DefaultOrdinalReferenceSystem that = (DefaultOrdinalReferenceSystem) object; return Objects.equals(this.ordinalEraSequence, that.ordinalEraSequence); } return false; } DefaultOrdinalReferenceSystem(Map<String, ?> properties, Collection<OrdinalEra> ordinalEraSequence); private  DefaultOrdinalReferenceSystem();  DefaultOrdinalReferenceSystem(final OrdinalReferenceSystem object); static DefaultOrdinalReferenceSystem castOrCopy(final OrdinalReferenceSystem object); @Override @XmlElement(name = "component", required = true) Collection<OrdinalEra> getComponents(); @Override boolean equals(Object object, ComparisonMode mode); @Override String toString();  }### Answer:
@Test public void testEquals() { assertFalse(ordinalReferenceSystem1.equals(null)); assertEquals(ordinalReferenceSystem1, ordinalReferenceSystem1); assertFalse(ordinalReferenceSystem1.equals(ordinalReferenceSystem2)); }