oops

Which can have both abstract and non-abstract methods?

• Interface

• Abstract Class

• Enum

• None of the above

What keyword is used to implement an interface?

• extend

• derive

• implement

• implements

Which one supports multiple inheritance in Java?

• Class

• Abstract class

• Interface

• Constructor

Can abstract class have private or protected members?

• Yes

• No

• Only public

• Only static

Which is true?

• Abstract class can implement an interface

• Interface can extend a class

• Abstract class must be final

• Interface can have constructors

Which of the following statements about constructors is TRUE?

• Constructors can be inherited

• Constructors can be overridden

• Constructors cannot be final

• Constructors can return a value

What will happen if a subclass overrides a method and gives it more restrictive access?

• Code compiles fine

• Runtime error

• Compile-time error

• JVM will ignore it

Which of these is true about method overloading?

• Same method name, same parameter types

• Same method name, different return type

• Same method name, different parameter list

• Must occur in different classes

What’s the output? class A { int x = 10; } class B extends A { int x = 20; } public class Test { public static void main(String[] args) { A obj = new B(); System.out.println(obj.x); } }

• 10

• 20

• Error

• 0

Which keyword is used to prevent a method from being overridden?

• static

• private

• final

• protected