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 1 and 2 2 and 4 2 and 3 3 and 4 1 and 3 1 and 2 2 and 4 2 and 3 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. You must add a return statement in method numberOfStudent(). Class School must be defined abstract. The method numberOfStudent() in class School must have a body. The keywords public and abstract cannot be used together. You must add a return statement in method numberOfStudent(). Class School must be defined abstract. The method numberOfStudent() in class School must have a body. 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); }} Runtime error Compilation error due to line 1 Compilation error due to line 2 Successful run and print 37 None of these Runtime error Compilation error due to line 1 Compilation error due to line 2 Successful run and print 37 None of these ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which two of the following are legal declarations for abstract classes and interfaces?1. final abstract class Test {}2. public static interface Test {}3. final public class Test {}4. protected abstract class Test {}5. protected interface Test {}6. abstract public class Test {} 3 and 6 3 and 5 2 and 4 5 and 6 1 and 2 3 and 6 3 and 5 2 and 4 5 and 6 1 and 2 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"); }} Nothing. b is an instance of b is an instance of A followed by b is an instance of b is an instance of Nothing. b is an instance of b is an instance of A followed by b is an instance of b is an instance of 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); }} None of these 12 10 Runtime Exception Compile with error None of these 12 10 Runtime Exception Compile with error ANSWER DOWNLOAD EXAMIANS APP
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