JAVA Interfaces and Abstract Classes
Which two of the following are legal declarations for abstract classes and interfaces?1. final abstract class Test {}2. public static interface Test {}3. final public class Test {}4. protected abstract class Test {}5. protected interface Test {}6. abstract public class Test {}

1 and 2
2 and 4
3 and 5
5 and 6
3 and 6

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JAVA Interfaces and Abstract Classes
What happens if the following program is compiled and executed?interface MyInterface{ void display();}interface MySubInterface extends MyInterface{ void display();}public class Test implements MySubInterface{ public void display(){ System.out.print("Welcome to Examveda."); } public static void main(String args[]){ Test t = new Test(); t.display(); }}

The code will lead to a compilation error as declaration of the display method has been provided in two interface.
The code will lead to a compilation error as the display method is not declared as abstract.
None of these
The code will lead to a compilation error due to public modifier while declaring the display method.
The code will compile and execute successfully showing the output Welcome to Examians.

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JAVA Interfaces and Abstract Classes
Determine output of the following code.interface A { }class C { }class D extends C { }class B extends D implements A { }public class Test extends Thread{ public static void main(String[] args){ B b = new B(); if (b instanceof A) System.out.println("b is an instance of A"); if (b instanceof C) System.out.println("b is an instance of C"); }}

Nothing.
b is an instance of
b is an instance of
b is an instance of A followed by b is an instance of

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JAVA Interfaces and Abstract Classes
Which of the following statements regarding abstract classes are true?

All of these
A subclass of a non-abstract superclass can be abstract.
An abstract class can be used as a data type.
A subclass can override a concrete method in a superclass to declare it abstract.
An abstract class can be extended.

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JAVA Interfaces and Abstract Classes
Which of the following class definitions defines a legal abstract class?

abstract class A { abstract void unfinished(); }
class A { abstract void unfinished(); }
public class abstract A { abstract void unfinished(); }
class A { abstract void unfinished() { } }

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