### Question:
Property extends ReadOnlyProperty<T> { public long getLastChanged() { return lastChanged; } Property(Class<T> aType, Object aOwner, String aName, T aDefaultValue, GameEventListener<PropertyChanged> aListener);  Property(Class<T> aType, Object aOwner, String aName, GameEventListener<PropertyChanged> aListener);  Property(Class<T> aType, Object aOwner, String aName, T aDefaultValue); void set(T aValue); void setQuietly(T aValue); long getLastChanged(); List<GameEventListener<PropertyChanged>> getChangeListener(); void addChangeListener(GameEventListener<PropertyChanged> aListener); void removeChangeListener(GameEventListener<PropertyChanged> aListener);  }### Answer:
@Test public void testGetLastChanged() throws Exception { Property<String> theProperty = new Property<String>(String.class, this, "property", "value"); long theLastChange = theProperty.getLastChanged(); assertTrue(theLastChange > 0); Thread.sleep(20); theProperty.set("value1"); assertTrue(theProperty.getLastChanged() > theLastChange); }