Java Classes and Objects MCQ - Multiple Choice Questions And Answers

Q. What is the purpose of a constructor in Java?

A. To initialize variables
B. To create objects
C. To destroy objects
D. To define methods
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Q. What does the 'new' keyword do in Java?

A. Creates a new method
B. Allocates memory for an object
C. Deletes an object
D. Calls a static method
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Q. Which keyword is used to inherit a class in Java?

A. super
B. this
C. extends
D. implements
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Q. Can a Java class extend multiple classes?

A. Yes
B. No
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Q. What is the difference between an object and a class in Java?

A. An object is created from a class
B. A class is created from an object
C. An object defines behavior
D. A class defines behavior
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Q. What is the default access modifier for class members in Java?

A. private
B. protected
C. public
D. package-private
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Q. What is method overloading in Java?

A. Redefining a method with the same name and parameters
B. Defining multiple methods with the same name but different parameters
C. Calling a method from within another method
D. Extending a method to add more functionality
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Q. What is method overriding in Java?

A. Redefining a static method
B. Redefining a method with the same name and parameters
C. Defining a method with a different name
D. Hiding a method implementation
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Q. What is the purpose of the Predicate functional interface in Java 8?

A. To produce results
B. To consume values
C. To filter elements based on a condition
D. To transform values
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Q. What is the difference between a class member and an instance member in Java?

A. A class member is static, an instance member is non-static
B. A class member is non-static, an instance member is static
C. A class member is private, an instance member is public
D. A class member is public, an instance member is private
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Q. What is the default access modifier in Java for class members if no access modifier is specified?

A. Default
B. Private
C. Public
D. Protected
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Q. What is the output of the following Java code snippet?

public class MyClass {
    private int number = 10;
    
    public void display() {
        System.out.println(number);
    }
}

public class Main {
    public static void main(String[] args) {
        MyClass obj = new MyClass();
        System.out.println(obj.number);
    }
}

A. 10
B. Error: Access Denied
C. 0
D. Compilation Error
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Q. Which access modifier makes a class member accessible only within the same package?

A. Private
B. Default
C. Public
D. Protected
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Q. What is the correct syntax for declaring a public method named "display" in Java?

A.

public void display() {
    // Method implementation
}

B.

private void display() {
    // Method implementation
}

C.

protected void display() {
    // Method implementation
}

D.

void display() {
    // Method implementation
}

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Q. Can a private method in Java be accessed from outside the class it belongs to?

A. Yes
B. No
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