Ans: The main advantages of using abstract class are as follows: 28. Analyze the following code. 3. Ans: Java compiler will generate compile time error. Java Method Overloading Interview Programs for Practice, 3. It is also called a complete method in java. __________ returns the number of days in a month. Ans: Abstraction hides the implementation details from users whereas, encapsulation wraps (binds) data and code into a single unit. This subclass constructor has a super keyword in the first line that calls constructor of an abstract class. That is, if the original list contained: $\mathrm{N}_{1}=5, \mathrm{N}_{2}=13, \mathrm{N}_{3}=8, \mathrm{N}_{4}=27, \mathrm{N}_{5}=10(\mathrm{k}=5)$ then when your algorithm has completed, the values stored in the list will be: $\mathrm{N}_{1}=10, \mathrm{N}_{2}=27, \mathrm{N}_{3}=8, \mathrm{N}_{4}=13, \mathrm{N}_{5}=5$. Show the output of running the class Test in the following code lines: Suppose A is an interface, B is a concrete class with a no-arg constructor that implements A. 8. 13. Analyze the following code. 24. What is JVM in Java, JVM Architecture, JIT Compiler, 8. Why abstract class has constructor even though you cannot create object? Assume Calendar calendar = new GregorianCalendar(). Extending and Implementing Interface in Java, 3. Is it possible to create an object of abstract class in Java? Identify the errors in the following code.
Top 15 Java Method Overriding Interview Programs for Practice, 2. b) When you need to be overridden in its non-abstract subclasses. When you instantiate an array, you can choose its location in memory. Top 32 Interview Questions on Polymorphism. Assume Calendar calendar = new GregorianCalendar(). As a general rule, an eof question should always come immediately after an input statement because the end-of-file condition will be detected at input. Difference between Method Overloading and Method Overriding, 7. Ans: We cannot create an object of abstract class but we can create an object of subclass of abstract class. They are: a) We cannot create an object of abstract class. Conditional Control Statements in Java, 2. When we create an object of subclass of an abstract class, it calls the constructor of subclass. What will happen if we do not override all abstract methods in subclass? If you create an individual method in subclass, the superclass reference cannot access that method. 19. What is the difference between abstract class and concrete class? Association vs Aggregation vs Composition, 2. Can abstract modifier applicable for variables? Download Eclipse IDE for Java Developers, 12. Thus, any programmer cannot add their own additional features in subclasses other than whatever is given in superclass. Ans: An abstract class can be used when we need to share the same method to all non-abstract sub classes with their own specific implementations. It hides all unwanted data so that users can work only with the required data. Labelled Loop in Java | Example Program, 5. Ans: No, It provides 0 to 100% abstraction. How to call m2() method in the above code? Ans: No, it cannot be private because the abstract method must be implemented in the child class. Abstract class makes programming better and more flexible by giving the scope of implementing abstract methods. Can an abstract class have constructor? Which of the following declares an abstract method in an abstract Java class? b) Interface (100%). 40 Java Abstract Class Interview Questions Answers, 8. It has simply a signature declaration followed by a semicolon. Access Modifiers Interview Questions Answers, 3. Download JDK (Java Development Kit) in Windows, 10. Rules of Exception Handling with Method Overriding, 4. 14. Private Constructor in Java | Use, Example, 3. Analyze the following code. If yes, what will be the output? Will the following code compile successfully? Can we make an abstract class without abstract keyword? Java Break Statement, Example Program, 12. Analyze the following code. Or, what will happen if we do not provide implementation for all abstract methods in subclass?
27. Ans: Yes, the above code will be compiled successfully. Copyright 2018-2022 Scientech Easy. Ans: We should create a reference of the superclass to access subclass features because superclass reference allows only to access those features of subclass which have already declared in superclass. They are as follows: a) Abstract class (0 to 100%) 6. If yes, what will be the output of program? We will have to override all abstract methods in subclass. Only objects of its non-abstract (or concrete) sub classes can be created. 2. Bytecode in Java | Bytecode vs Machine code, 6. Identifiers in Java | Rules of Identifiers, 1. Assume Calendar calendar = new GregorianCalendar(). The java.lang.Number and its subclasses are introduced in Chapter 11. Which of the following statements are true? When to use Method overloading in Java Project, 4. 50 Java Interface Interview Programming Questions, 1. Thus, the constructors of an abstract class are used from constructor of its subclass. Can an abstract method be declared with private modifier? Will the code compile successfully? Ans: There are mainly two differences between an abstract class and concrete class. If we declare it as private, we cannot implement it from outside the class. Simple Java Program in Eclipse, Compile, Run, 14. Ans: No, we cannot define an abstract method in non-abstract class. Which of the following statements regarding abstract methods is false? Programmer can implement abstract method to perform different tasks depending on the need. Realtime Use of Interface in Java Application in Java, 5. If the abstract class doesnt have constructor, a class that extends that abstract class will not get compiled. Here, we have listed the best collection of 40 Java abstract class interview questions with answers. Ans: There are two ways to implement abstraction in java. Ans: Yes, the code will be compiled successfully.
Compile time, Runtime Polymorphism in Java, 3. Top 5 Encapsulation Programs in Java for Practice, 4. 9. Is it possible that an abstract class can have without any abstract method? What is the best suitable relationship between Company and Employee? A customer in a store is purchasing five items. Which of the following statements is false? Ans: A method which is declared with abstract modifier and has no implementation (means no body) is called abstract method in java. T F If you leave an element uninitialized, you do not have to leave all the ones that follow it uninitialized. 22. Is abstract class allow to define private, final, static, and concrete methods? How to call Methods with Parameters in Java, 5. Which of the following is a correct interface? It is not possible but we can create an object of its subclass. Design and implement an algorithm that is given as input an integer value $k \geq 0$ and a list of k numbers $\mathrm{N}_{1}, \mathrm{N}_{2}, \ldots, \mathrm{N}_{\mathrm{k}}$ Your algorithm should reverse the order of the numbers in the list. 23. Which of the following is correct? Is abstract class a pure abstraction in Java? Continue Statement in Java, Example Program, 13. The output is One. Can we define an abstract method inside non-abstract class (concrete class)? If yes, how? Will the given code compile successfully? It does not contain any body. 25. What is the difference between Abstraction and Encapsulation? The output is m1 in class B. The Rational class in this chapter is defined as a subclass of java.lang.Number. If else in Java | Nested if-else, Example, 4. The above code will generate a compile-time error. 18. What is the advantage of Abstract class in Java? 22 Vital Difference between C++ and Java, 4.
16. Ans: No, the code will not be compiled successfully because we cannot reduce the visibility of the inherited method from A. Ans: Yes, the code will be compiled successfully. Why should we create reference to superclass (abstract class reference)?
What is the output of running class Test? a) When the same method has to perform different tasks depending on the object calling it. Therefore, we will get a compile-time error. Which of the following statements is correct? How to define it? Is it possible to achieve multiple inheritance through abstract class? __________ returns the week of the year. Which among the following code have errors? We have also covered interview programming exercise for best practice. Ans: a, b, f, g, i.
14 copies of a code module are to be executed in parallel on identical processors organized into two communicating clusters, A and B. The GeometricObject and Circle classes are defined in this chapter. What is the best suitable relationship between Employee and Faculty? 3. 12 Difference between Abstract class and Interface, 7. Cluster A contains 16 processors and cluster B contains 32 processors. Which of the following statements is correct? 30. Java Upcasting and Downcasting with Example, 7. 21. Automatic type Promotion in Method overloading, 6. If a base class has a non-virtual member function named print, and a pointer variable of that class is pointing to a derived object, then the code ptr->print( ); calls. Ans: An abstract class in java is a class that is declared with an abstract keyword.
Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a no-arg constructor. Abstract Class Interview Questions and Answers for best Practice, Java Abstract Class Interview Program Questions, Top 85+ OOPs Interview Questions in Java with Answers, 50 Java Interface Interview Programming Questions, Bytecode in Java | Bytecode vs Machine code, What is JVM in Java, JVM Architecture, JIT Compiler, Interpreter in Java | Interpreter vs Compiler, Download JDK (Java Development Kit) in Windows, Simple Java Program in Eclipse, Compile, Run, Identifiers in Java | Rules of Identifiers, If else in Java | Nested if-else, Example, Continue Statement in Java, Example Program, How to call Methods with Parameters in Java, Private Constructor in Java | Use, Example, Access Modifiers Interview Questions Answers, Top 5 Encapsulation Programs in Java for Practice, 12 Java Encapsulation Interview Questions Answers, Behavior of Access modifiers in case of Inheritance, 10 Java Inheritance Interview Programs for Practice, Top 50 Java Inheritance Interview Questions Answers, Association vs Aggregation vs Composition, When to use Method overloading in Java Project, Automatic type Promotion in Method overloading, Java Upcasting and Downcasting with Example, Java Method Overloading Interview Programs for Practice, Rules of Exception Handling with Method Overriding, Difference between Method Overloading and Method Overriding, Top 15 Java Method Overriding Interview Programs for Practice, Extending and Implementing Interface in Java, Realtime Use of Interface in Java Application in Java, 12 Difference between Abstract class and Interface, 40 Java Abstract Class Interview Questions Answers, Compile time, Runtime Polymorphism in Java, Top 32 Interview Questions on Polymorphism. All rights reserved. b) It can have zero or more abstract methods that are not allowed in a non-abstract class (concrete class). Can an abstract method be declared as static? Write a program that asks for the price of Which of the following class definitions defines a legal abstract class?