JAVA Interfaces and Abstract Classes Which of the following statements regarding abstract classes are true? All of these An abstract class can be used as a data type. 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 extended. All of these An abstract class can be used as a data type. 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 extended. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes interface Test{ int p = 10; //line 1 public int q = 20; //line 2 public static int r = 30; //line 3 public static final int s = 40; //line 4}Which of the above line will give compilation error? 4 1 3 2 None of these 4 1 3 2 None of these 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 2 2 and 3 3 and 4 1 and 3 2 and 4 1 and 2 2 and 3 3 and 4 1 and 3 2 and 4 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? Class School must be defined abstract. You must add a return statement in method numberOfStudent(). The method numberOfStudent() in class School must have a body. The keywords public and abstract cannot be used together. Class School must be defined abstract. You must add a return statement in method numberOfStudent(). The method numberOfStudent() in class School must have a body. The keywords public and abstract cannot be used together. 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) }} 1 and 2 2 and 3 1 and 3 4 and 5 3 and 4 1 and 2 2 and 3 1 and 3 4 and 5 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful When it doesn't make sense to have objects of that class. 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. To force developers to extend the class not to use its capabilities. When it doesn't make sense to have objects of that class. 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. To force developers to extend the class not to use its capabilities. ANSWER DOWNLOAD EXAMIANS APP
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