Section 23.6.4 Check Point Questions2 questions 

Which of the following statements are wrong?

1  Heap<Object> heap1 = new Heap<>();
2  Heap<Number> heap2 = new Heap<>();
3  Heap<BigInteger> heap3 = new Heap<>();
4  Heap<Calendar> heap4 = new Heap<>();
5  Heap<> heap5 = new Heap<>();

What is the return value from invoking the remove method if the heap is empty?