@Test public void testIsLeaf() { assertTrue(zero.isLeaf()); assertTrue(one.isLeaf()); assertFalse(zeroZero.isLeaf()); assertFalse(zeroOne.isLeaf()); assertFalse(oneZero.isLeaf()); assertFalse(oneOne.isLeaf()); }
abstract boolean isLeaf();
ID { abstract boolean isLeaf(); }
ID { abstract boolean isLeaf();  }
ID { abstract boolean isLeaf();   }
ID { abstract boolean isLeaf();    }