JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true? An abstract class can be used as a data type. A subclass can override a concrete method in a superclass to declare it abstract. All of these A subclass of a non-abstract superclass can be abstract. An abstract class can be extended. An abstract class can be used as a data type. A subclass can override a concrete method in a superclass to declare it abstract. All of these A subclass of a non-abstract superclass can be abstract. An abstract class can be extended. 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? You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. The method numberOfStudent() in class School must have a body. Class School must be defined abstract. You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. The method numberOfStudent() in class School must have a body. Class School must be defined abstract. 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(); 1 and 3 1 and 2 2 and 3 3 and 4 2 and 4 1 and 3 1 and 2 2 and 3 3 and 4 2 and 4 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 3 3 and 4 1 and 2 4 and 5 2 and 3 1 and 3 3 and 4 1 and 2 4 and 5 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will be the output for the below code ?public interface TestInf{ int i =10;}public class Test{ public static void main(String... args){ TestInf.i=12; System.out.println(TestInf.i); }} 10 12 None of these Compile with error Runtime Exception 10 12 None of these Compile with error Runtime Exception 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 default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. When it makes 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. When default implementations of some methods are not desirable. When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. To prevent developers from further extending the class. ANSWER DOWNLOAD EXAMIANS APP
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