### Question:
NumberProperty extends BaseProperty { @Override public int hashCode() { HashCodeBuilder builder = new HashCodeBuilder(); builder.appendSuper(super.hashCode()); builder.append(getValue()); return builder.toHashCode(); } NumberProperty(); @Override Object getValue(); @Override void setValue(Object value); @Override String toText(); @Override boolean equals(Object obj); @Override int hashCode(); @Override NumberProperty clone();  }### Answer:
@Test public void testHashCode() { final Number value = 101; NumberProperty n1 = new IntegerProperty(); NumberProperty n2 = new IntegerProperty(); n1.setValue(value); n2.setValue(value); Assert.assertEquals(n1.hashCode(), n2.hashCode()); }