REVATURE COMPREHENSIVE STUDY GUIDE
2026 QUESTIONS WITH CORRECT
SOLUTIONS GRADED A+
◉OOP Components. Answer: Object
Classes
Inheritance
Polymorphism
Abstraction
Encapsulation
◉Object. Answer: - Any entity that has state and behavior
- defined as an instance of a class
- contains an address and takes up some space in memory
- can communicate without knowing the details of each other's data
or code
◉Class. Answer: - templates that are used to create objects, and to
define object data types and methods
- Class doesn't consume any space
,◉Object-Oriented vs. Procedure-Oriented. Answer: - OOPs makes
development and maintenance easier whereas in a procedure-
oriented programming language it is not easy to manage if code
grows as project size increases.
- OOPs provides data hiding whereas in a procedure-oriented
programming language a global data can be accessed from
anywhere.
◉Constructor. Answer: - a special type of method which is used to
initialize the object
- called when an instance of the object is created, and memory is
allocated for the object
◉Rules on Creating a Constructor. Answer: 1. Constructor name
must be the same as its class name
2. A Constructor must have no explicit return type
3. A Java constructor cannot be abstract, static, final, and
synchronized
◉Types of Constructors. Answer: Default Constructor - default call
to super()
Parameterized Constructor
,◉Constructor Overloading. Answer: a technique of having more than
one constructor with different parameter lists
◉Constructor vs. Method: Constructor. Answer: 1. A constructor is
used to initialize the state of an object.
2. A constructor must not have a return type.
3. The constructor is invoked implicitly.
4. The Java compiler provides a default constructor if you don't have
any constructor in a class.
5. The constructor name must be same as the class name.
◉Constructor vs. Method: Method. Answer: 1. A method is used to
expose the behavior of an object.
2. A method must have a return type.
3. The method is invoked explicitly.
4. The method is not provided by the compiler in any case.
5. The method name may or may not be same as class name.
◉Inheritance. Answer: - one object acquires all the properties and
behaviors of a parent object
- create new classes that are built upon existing classes (reuse
methods and fields of parent class)
- IS-A relationship (parent-child)
, ◉Advantages of Inheritances. Answer: - For Method Overriding (so
runtime polymorphism can be achieved).
- For Code Reusability.
◉Sub Class. Answer: Subclass is a class which inherits the other
class. It is also called a derived class, extended class, or child class.
◉Super Class. Answer: Superclass is the class from where a subclass
inherits the features. It is also called a base class or a parent class.
◉Reusability. Answer: a mechanism which facilitates you to reuse
the fields and methods of the existing class when you create a new
class. You can use the same fields and methods already defined in
the previous class.
◉Syntax for Inheritance. Answer: class SubclassName extends
SuperclassName {}
◉Single Inheritance. Answer: ClassA <- ClassB
◉Multilevel Inheritance. Answer: ClassA <- ClassB <- ClassC
◉Hierarchical Inheritance. Answer: ClassB -> ClassA <- ClassC
2026 QUESTIONS WITH CORRECT
SOLUTIONS GRADED A+
◉OOP Components. Answer: Object
Classes
Inheritance
Polymorphism
Abstraction
Encapsulation
◉Object. Answer: - Any entity that has state and behavior
- defined as an instance of a class
- contains an address and takes up some space in memory
- can communicate without knowing the details of each other's data
or code
◉Class. Answer: - templates that are used to create objects, and to
define object data types and methods
- Class doesn't consume any space
,◉Object-Oriented vs. Procedure-Oriented. Answer: - OOPs makes
development and maintenance easier whereas in a procedure-
oriented programming language it is not easy to manage if code
grows as project size increases.
- OOPs provides data hiding whereas in a procedure-oriented
programming language a global data can be accessed from
anywhere.
◉Constructor. Answer: - a special type of method which is used to
initialize the object
- called when an instance of the object is created, and memory is
allocated for the object
◉Rules on Creating a Constructor. Answer: 1. Constructor name
must be the same as its class name
2. A Constructor must have no explicit return type
3. A Java constructor cannot be abstract, static, final, and
synchronized
◉Types of Constructors. Answer: Default Constructor - default call
to super()
Parameterized Constructor
,◉Constructor Overloading. Answer: a technique of having more than
one constructor with different parameter lists
◉Constructor vs. Method: Constructor. Answer: 1. A constructor is
used to initialize the state of an object.
2. A constructor must not have a return type.
3. The constructor is invoked implicitly.
4. The Java compiler provides a default constructor if you don't have
any constructor in a class.
5. The constructor name must be same as the class name.
◉Constructor vs. Method: Method. Answer: 1. A method is used to
expose the behavior of an object.
2. A method must have a return type.
3. The method is invoked explicitly.
4. The method is not provided by the compiler in any case.
5. The method name may or may not be same as class name.
◉Inheritance. Answer: - one object acquires all the properties and
behaviors of a parent object
- create new classes that are built upon existing classes (reuse
methods and fields of parent class)
- IS-A relationship (parent-child)
, ◉Advantages of Inheritances. Answer: - For Method Overriding (so
runtime polymorphism can be achieved).
- For Code Reusability.
◉Sub Class. Answer: Subclass is a class which inherits the other
class. It is also called a derived class, extended class, or child class.
◉Super Class. Answer: Superclass is the class from where a subclass
inherits the features. It is also called a base class or a parent class.
◉Reusability. Answer: a mechanism which facilitates you to reuse
the fields and methods of the existing class when you create a new
class. You can use the same fields and methods already defined in
the previous class.
◉Syntax for Inheritance. Answer: class SubclassName extends
SuperclassName {}
◉Single Inheritance. Answer: ClassA <- ClassB
◉Multilevel Inheritance. Answer: ClassA <- ClassB <- ClassC
◉Hierarchical Inheritance. Answer: ClassB -> ClassA <- ClassC
