Q.What Is a Package?
A package is a namespace that organizes a set of related classes
and interfaces. Conceptually we can think of packages as being similar to
different folders on our computer. We might keep HTML pages in one folder,
images in another, and scripts or applications in yet another. Because software
written in the Java programming language can be composed of hundreds or
thousands of individual classes, it makes sense to keep things organized by
placing related classes and interfaces into packages.
Q. Mention any two
attributes required for class declaration.
Ans: Variables and function or state and behaviour.
Q. Differentiate between
base and derived class.
The base class is a class whose properties will be inherited and
the derived class is a class which inherits the base class. E.g. Of base class
is Super and derived class is sub.
(Constructors)
Q. Define Constructor.
When a constructor is called?
Ans: A constructor is special member function that is
automatically called when an instance of a class is declared.
A constructor is called when an object of the class is created.
Q. Why do we need a
constructor as a class member?
Ans: Constructors have one purpose in life: to create an
instance of a class.
Q. What is a default
constructor? Why is a default constructor called so?
Ans: A default constructor is a special member function that
initializes the objects.
It is called because it declares no parameters. It gets invoked
without any parameter
Q. What are the
characteristics of constructor function?
Ans: Constructors are the special member functions and have the
same name as class and it is called automatically when object being create.
Q. What is parameterisedconstructor?
Ans: The constructors which can take different parameters are
referred to as Parameterised Constructors.
Q. What is constructor
overloading?.
Ans:
Defining more than one constructor for a class where they differ in the
parameter types or number of parameters passed to the constructor is called
overloading.
