BooleanHolder extends AbstractValueHolder { @Override public Boolean getValue() { return value; } BooleanHolder(Boolean value); @Override Boolean getValue(); @Override boolean booleanValue(); @Override Boolean getBoolean();  }
@Test public void testGetValue() { assertEquals(b1, h1.getValue()); assertEquals(b2, h2.getValue()); assertNull(h3.getValue()); }
@Test public void testCompareTo() { BooleanHolder[] array = { new BooleanHolder(true), new BooleanHolder(null), new BooleanHolder(false) }; Arrays.sort(array); assertEquals(null, array[0].getValue()); assertEquals(false, (boolean) array[1].getValue()); assertEquals(true, (boolean) array[2].getValue()); }