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    • 50 Java Language MCQs with Answers

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    Question 1

    What will be the output of this program?

    Java 
    abstract class Parent {     abstract void show(); } class Child extends Parent {     void show() {         System.out.println("Child class method");     } } public class Main {     public static void main(String[] args) {         Parent p = new Child();         p.show();     } }


    • Compilation Error

    • Runtime Error


    • Child class method

    • No Output

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    Question 2

    What happens if an abstract class does not have any abstract methods?

    • It will not compile.

    • The class can still be abstract.

    • Java will automatically provide an abstract method.

    • It becomes a concrete class.

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    Question 3

    What will be the output of this code?

    Java 
    class Animal {     void makeSound() {         System.out.println("Animal makes a sound");     } } class Dog extends Animal {     void makeSound() {         System.out.println("Dog barks");     } } public class Main {     public static void main(String[] args) {         Animal a = new Dog();         a.makeSound();     } }


    • Animal makes a sound


    • Dog barks

    • Compilation error


    • Runtime error

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    Question 4

    Which of the following statements about inheritance is false?


    • Java supports single inheritance.


    • Java allows multiple class inheritance using extends.

    • Interfaces can be used to achieve multiple inheritance.


    • The super keyword can be used to invoke the parent class constructor.


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    Question 5

    Which of the following statements about abstract classes is correct?


    • Abstract classes cannot have constructors.

    • Abstract classes cannot have static methods.


    • An object of an abstract class cannot be instantiated.

    • Abstract classes cannot have final methods.

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    Question 6

    In Java, we can make a class abstract by

    • Declaring it abstract using the abstract keyword.

    • Making at least one method final.

    • Declaring all methods as static.

    • Declaring at least one method as abstract.

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    Question 7

    Which of the following is true about an abstract class in Java?

    • An abstract class can be instantiated directly.

    • An abstract class can contain both abstract and non-abstract methods.

    • All methods in an abstract class must be abstract.

    • An abstract class cannot have a constructor.

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    Question 8

    Type IV JDBC driver is a driver

    • which is written in C++

    • which requires an intermediate layer

    • which communicates through Java sockets

    • which translates JDBC function calls into API not native to DBMS

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    Question 9

    Predict the output of the following program.

    Java 
    abstract class demo {     public int a;     demo()     {         a = 10;     }      abstract public void set();          abstract final public void get();  }  class Test extends demo {      public void set(int a)     {         this.a = a;     }      final public void get()     {         System.out.println("a = " + a);     }      public static void main(String[] args)     {         Test obj = new Test();         obj.set(20);         obj.get();     } }

    • a = 10

    • a = 20

    • Compilation error

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    Question 10

    Which of the following is FALSE about abstract classes in Java

    • If we derive an abstract class and do not implement all the abstract methods, then the derived class should also be marked as abstract using \'abstract\' keyword

    • Abstract classes can have constructors

    • A class can be made abstract without any abstract method

    • A class can inherit from multiple abstract classes.

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    There are 50 questions to complete.

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