JAVA Interfaces and Abstract Classes
What is the output for the below code ?interface A{ public void printValue();}1. public class Test{2. public static void main (String[] args){3. A a1 = new A(){4. public void printValue(){5. System.out.println("A");6. }7. };8. a1.printValue();9. }10. }

null
None of these
Compilation fails due to an error on line 8
A
Compilation fails due to an error on line 3

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JAVA Interfaces and Abstract Classes
Given the following piece of code:public interface Guard{ void doYourJob();}abstract public class Dog implements Guard{ }which of the following statements is correct?

This code will not compile, because in the declaration of class Dog we must use the keyword extends instead of implements.
This code will not compile, because method doYourJob() in interface Guard must be defined abstract.
This code will not compile, because class Dog must implement method doYourJob() from interface Guard.
This code will compile without any errors.

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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
What will be the output?interface A{public void method();}class One{public void method(){System.out.println("Class One method");}}class Two extends One implements A{public void method(){System.out.println("Class Two method");}}public class Test extends Two{public static void main(String[] args){A a = new Two();a.method();}}

compiles fine but print nothing
Compilation Error
will print Class Two method
None of these
will print Class One method

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JAVA Interfaces and Abstract Classes
interface Base{ boolean m1 (); byte m2(short s);}which two code fragments will compile?1. interface Base2 implements Base {}2. abstract class Class2 extends Base { public boolean m1(){ return true; }}3. abstract class Class2 implements Base {}4. abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }}5. abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }}

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

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