Intermidiate Java Concepts

Question 1

What is a constructor?

Answer 1

It is a special method that is called when an object of a class is created, it is used to initialize an object of a class.

Question 2

What are the types of constturctors?

Answer 2

1. Default constructror
2. No parameter constructor
3. Parameterized constructor

Question 3

What is a default constructor?

Answer 3

It is no parameter constructor that is automaticaly provided by the compiler, if not consturctor is defined by the programmer.

Question 4

what are the possible access modifiers in java and what are thier meanings

Answer 4

1. Private: accesible only withing the same class
2. Public: Accesible from any class
3. Protected: Accessible within the same package or sub classes
4. default: Accessible within the same package

Question 5

What are the types of polymorphism?

Answer 5

1. Compile Time Polymorphism (mehtod overloading): thesame method name, different type or number of parameters
2. Run time polymorphism (method overriding): When a subclasss provides a specific implementation of a metod alread define in its parent or supper class

Question 6

What is an abstact class?

Answer 6

It is a class that objects cannot be created from it may contain abstact methods and concreate methods

Question 7

What is an abstract method?

Answer 7

It is a method with no body or implementation