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. An abstract class can be extended. A subclass can override a concrete method in a superclass to declare it abstract. A subclass of a non-abstract superclass can be abstract. All of these An abstract class can be used as a data type. An abstract class can be extended. A subclass can override a concrete method in a superclass to declare it abstract. A subclass of a non-abstract superclass can be abstract. All of these ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful When default implementations of some methods are not desirable. When it makes sense to have objects of that 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. To prevent developers from further extending the class. When default implementations of some methods are not desirable. When it makes sense to have objects of that 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. To prevent developers from further extending the class. 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(); }} The code will lead to a compilation error as the display method is not declared as abstract. 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 compile and execute successfully showing the output Welcome to Examians. The code will lead to a compilation error due to public modifier while declaring the display method. The code will lead to a compilation error as the display method is not declared as abstract. 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 compile and execute successfully showing the output Welcome to Examians. The code will lead to a compilation error due to public modifier while declaring the display method. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Runnable is a _____ . abstract class method class vaiable interface abstract class method class vaiable interface 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 class Dog must implement method doYourJob() from interface Guard. This code will not compile, because method doYourJob() in interface Guard must be defined abstract. 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 class Dog must implement method doYourJob() from interface Guard. This code will not compile, because method doYourJob() in interface Guard must be defined abstract. This code will compile without any errors. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Determine output of the following code.interface A { }class C { }class D extends C { }class B extends D implements A { }public class Test extends Thread{ public static void main(String[] args){ B b = new B(); if (b instanceof A) System.out.println("b is an instance of A"); if (b instanceof C) System.out.println("b is an instance of C"); }} b is an instance of b is an instance of A followed by b is an instance of Nothing. b is an instance of b is an instance of b is an instance of A followed by b is an instance of Nothing. b is an instance of ANSWER DOWNLOAD EXAMIANS APP
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