JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true? A subclass of a non-abstract superclass can be abstract. A subclass can override a concrete method in a superclass to declare it abstract. An abstract class can be used as a data type. An abstract class can be extended. All of these A subclass of a non-abstract superclass can be abstract. A subclass can override a concrete method in a superclass to declare it abstract. An abstract class can be used as a data type. An abstract class can be extended. All of these 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) }} 3 and 4 2 and 3 1 and 2 4 and 5 1 and 3 3 and 4 2 and 3 1 and 2 4 and 5 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will be the output?1. public interface InfA{2. protected String getName();3. }public class Test implements InfA{ public String getName(){ return "test-name"; } public static void main (String[] args){ Test t = new Test(); System.out.println(t.getName()); }} Compilation fails due to an error on lines 2 None of these Compilation fails due to an error on lines 1 test-name Compilation succeed but Runtime Exception Compilation fails due to an error on lines 2 None of these Compilation fails due to an error on lines 1 test-name Compilation succeed but Runtime Exception ANSWER DOWNLOAD EXAMIANS APP
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(); }} None of these 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. 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. None of these 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. 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. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful To force developers to extend the class not to use its capabilities. When it makes sense to have objects of that class. When default implementations of some methods are not desirable. To prevent developers from further extending the class. When it doesn't make sense to have objects of that class. To force developers to extend the class not to use its capabilities. When it makes sense to have objects of that class. When default implementations of some methods are not desirable. To prevent developers from further extending the class. When it doesn't make sense to have objects of that class. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B(); 2 and 4 1 and 2 3 and 4 2 and 3 1 and 3 2 and 4 1 and 2 3 and 4 2 and 3 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
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