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 1 and 3 2 and 3 2 and 4 3 and 4 1 and 2 1 and 3 2 and 3 2 and 4 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will be the output when the following program is compiled and executed?abstract class TestAbstract{ String my_name; String myName(){ my_name = "Examveda"; return my_name; } abstract void display();}public class Test extends TestAbstract{ void display(){ String n = myName(); System.out.print("My name is "+ n); } public static void main(String args[]){ Test t = new Test(); t.display(); }} Compilation error as class can not be declared as abstract. Program compiles but leads to runtime exception. None of these Compilation error occurs as the abstract class TestAbstract contains a non-abstract method. Program will compile and execute successfully and prints Compilation error as class can not be declared as abstract. Program compiles but leads to runtime exception. None of these Compilation error occurs as the abstract class TestAbstract contains a non-abstract method. Program will compile and execute successfully and prints 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? 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. 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. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which of the following declares an abstract method in an abstract Java class? public abstract void method(); public abstract method(); public void method() {} public abstract void method() {} public void abstract Method(); public abstract void method(); public abstract method(); public void method() {} public abstract void method() {} public void abstract Method(); 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 Which of the following class definitions defines a legal abstract class? public class abstract A { abstract void unfinished(); } abstract class A { abstract void unfinished(); } class A { abstract void unfinished(); } class A { abstract void unfinished() { } } public class abstract A { abstract void unfinished(); } abstract class A { abstract void unfinished(); } class A { abstract void unfinished(); } class A { abstract void unfinished() { } } ANSWER DOWNLOAD EXAMIANS APP
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