Indicate whether the following statements are true or false in the Java programming Language:

1. The default access modifier allows access only within the same class. 
   True

   False
    //Select the answer

2. A variable that can hold a reference to an object of class A can also hold a reference to an object belonging to any subclass of A. 
   True

   False
    //Select the answer

3. An upcast from a subclass to a superclass must be explicitly casted to the superclass type.
   False

   True
    //Select the answer

4. A method can be overloaded by changing only the argument list. 
   True

   False
    //Select the answer

5. Method overloading uses the actual type of the class at runtime to decide which method to invoke. 
   True

   False
    //Select the answer

6. Abstract classes in Java cannot define constructors because they are never directly instantiated.
   True

   False
    //Select the answer