Questions about pointers from cassido's 1/7/19 newsletter

pointers.txt

- What is the difference between passing by value and passing by reference?
  By value: Passes the value of the memory address that the pointer points to.
  By reference: Passes an alias to “reference” the variable passed in. 
  
- How can pointers be used with inherited or abstract classes?
  Using static methods.
  
- What does it mean for a pointer to be null?
  The pointer does not point to any address in memory. 
  
- What happens when you use the dereference operator (&) on a null pointer?
  NullPointerException.