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

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

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

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JAVA Interfaces and Abstract Classes
In Java, declaring a class abstract is useful

When default implementations of some methods are not desirable.
When it makes sense to have objects of that class.
When it doesn't make sense to have objects of that class.
To prevent developers from further extending the class.
To force developers to extend the class not to use its capabilities.

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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. }

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

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