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

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

ANSWER DOWNLOAD EXAMIANS APP

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();}}

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

ANSWER DOWNLOAD EXAMIANS APP

JAVA Interfaces and Abstract Classes
Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true?

The keywords public and abstract cannot be used together.
You must add a return statement in method numberOfStudent().
Class School must be defined abstract.
The method numberOfStudent() in class School must have a body.

ANSWER DOWNLOAD EXAMIANS APP

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) }}

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

ANSWER DOWNLOAD EXAMIANS APP