JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful When default implementations of some methods are not desirable. To force developers to extend the class not to use its capabilities. To prevent developers from further extending the class. 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 force developers to extend the class not to use its capabilities. To prevent developers from further extending the class. When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. 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 3 and 4 4 and 5 2 and 3 1 and 3 1 and 2 3 and 4 4 and 5 2 and 3 1 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 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. The keywords public and abstract cannot be used together. You must add a return statement in method numberOfStudent(). Class School must be defined abstract. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes What will be the output?1. public interface InfA{2. protected String getName();3. }public class Test implements InfA{ public String getName(){ return "test-name"; } public static void main (String[] args){ Test t = new Test(); System.out.println(t.getName()); }} Compilation fails due to an error on lines 2 None of these Compilation fails due to an error on lines 1 test-name Compilation succeed but Runtime Exception Compilation fails due to an error on lines 2 None of these Compilation fails due to an error on lines 1 test-name Compilation succeed but Runtime Exception ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which of the following declares an abstract method in an abstract Java class? public void method() {} public abstract void method(); public abstract void method() {} public abstract method(); public void abstract Method(); public void method() {} public abstract void method(); public abstract void method() {} public abstract method(); public void abstract Method(); 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 2 2 and 4 1 and 3 2 and 3 3 and 4 1 and 2 2 and 4 1 and 3 2 and 3 ANSWER DOWNLOAD EXAMIANS APP
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