UNIT1

Which is not a feature of OOP?

• Encapsulation

• Inheritance

• Compilation

• Polymorphism

Java supports multiple inheritance using:

• class

• abstract class

• interface

• object

Keyword to inherit class

• this

• extends

• super

• implements

int x = 2;

x *= 3 + 4;

System.out.println(x);

• 14

• 10

• 6

• Compilation error

System.out.println(10 + 20 + "Java" + 10 + 20);

• 30Java1020

• Java102030

• Java30

• Compilation error

Which of the following correctly creates an object in Java?

• MyClass obj = MyClass();

• obj = new MyClass;

• MyClass obj = new MyClass();

• class MyClass = new Object();

Which statement is true about abstract classes?

• They can be instantiated

• They can't have any method body

• They can have both abstract and non-abstract methods

• They are always final

Which of the following is valid usage of abstract class that does not cause error?

abstract class A {

abstract void display();

}

class B extends A {}

• No error

• Class B must implement display()

• Abstract class must be final

• Abstract class can't be inherited**

What happens when you try to instantiate an abstract class?

• It compiles and runs

• Compile-time error

• Object is created

• JVM throws error at runtime

Fill in the blank to refer to current class’s variable:

public void setName(String name) {

_____ .name = name;

}

• this

• super

• final

• abstract