JavaQuizzes

Quiz Guidelines

 

Multiple Choice Question

Submitted by heartin on Sun, 09/13/2015 - 09:26
QID: 
37

Given:

interface I {
}

class A implements I {
}

class B extends A {
}

class C {
}

public class TestClass1 {
	public static void main(String[] args) {
		I i = new B();
		B b = new B();
		C c = new C();
		if (i instanceof I)
			System.out.println("i is a I");
		if (b instanceof A)
			System.out.println("b is a A");
		if (c instanceof A)
			System.out.println("c is a A");
	}
}

 

What will be printed when the above code is compiled and run?

Select 1 option

A. It will not compile.

B. It will throw an exception when run.

C. i is a I
    b is a A

D. i is a I

E. b is a A

F. c is a A

Descriptive Question

Submitted by heartin on Mon, 09/14/2015 - 10:21
QID: 
38

Find output or error: 

class OOP1 {

void x (int i) {

System.out.println("one");

}

void x (String s) {

System.out.println("two");

}

void x (double d) {

System.out.println("three");

}

public static void main(String[] args) {

new OOP1().x (4.0);

}

} 

 

Descriptive Question

Submitted by heartin on Mon, 09/14/2015 - 10:49
QID: 
39

Given:

public class X implements Z {

public String toString() {

return "I am X";

}

public static void main(String[] args) {

Y myY = new Y();

X myX = myY;

Z myZ = myX;

System.out.println(myZ);

}

}

class Y extends X {

public String toString() {

return "I am Y";

}

}

interface Z {}

What is the reference type of myZ and what is the type of the object it references? 

Descriptive Question

Submitted by heartin on Mon, 09/14/2015 - 10:51
QID: 
40

Find output or error: 

class OOP2 {

int x(double d) {

System.out.println("one");

return 0;

}

String x(double d) {

System.out.println("two");

return null;

}

double x(double d) {

System.out.println("three");

return 0.0;

}

public static void main(String[] args) {

new OOP2().x(4.0)

}

} 

 

Descriptive Question

Submitted by heartin on Mon, 09/14/2015 - 10:57
QID: 
41

Find output or error:

public class NullCheck {

public void myMethod(String str) {

System.out.println("String");

}

public void myMethod(Double d) {

System.out.println("Double");

}

public static void main(String[] args) {

NullCheck nc = new NullCheck();

nc.myMethod(null);

}

}

 

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