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. An abstract class can be extended. A subclass can override a concrete method in a superclass to declare it abstract. An abstract class can be used as a data type. All of these A subclass of a non-abstract superclass can be abstract. An abstract class can be extended. A subclass can override a concrete method in a superclass to declare it abstract. An abstract class can be used as a data type. All of these 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. To prevent developers from further extending the 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. 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. When it makes sense to have objects of that class. When default implementations of some methods are not desirable. 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(); 3 and 4 1 and 3 2 and 4 2 and 3 1 and 2 3 and 4 1 and 3 2 and 4 2 and 3 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will happen after compiling this program code?abstract class MyClass{ //line 1 private int a, b; public void call(int a, int b){ this.a = a; this.b = b; System.out.print(a+b); }}public class Test{ public static void main(String args[]){ MyClass m = new MyClass(); //line 2 m.call(12,25); }} Compilation error due to line 1 None of these Runtime error Successful run and print 37 Compilation error due to line 2 Compilation error due to line 1 None of these Runtime error Successful run and print 37 Compilation error due to line 2 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Given the following piece of code:public interface Guard{ void doYourJob();}abstract public class Dog implements Guard{ }which of the following statements is correct? This code will not compile, because in the declaration of class Dog we must use the keyword extends instead of implements. This code will not compile, because method doYourJob() in interface Guard must be defined abstract. This code will not compile, because class Dog must implement method doYourJob() from interface Guard. This code will compile without any errors. This code will not compile, because in the declaration of class Dog we must use the keyword extends instead of implements. This code will not compile, because method doYourJob() in interface Guard must be defined abstract. This code will not compile, because class Dog must implement method doYourJob() from interface Guard. This code will compile without any errors. 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? 2 3 None of these 1 4 2 3 None of these 1 4 ANSWER DOWNLOAD EXAMIANS APP
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