DECLARATION AND ACCESS CONTROL QUIZ

Determine output:class A{{System.out.print("b1 ");}public A(){System.out.print("b2 ");}}class B extends A{static{System.out.print("r1 ");}public B(){System.out.print("r2 ");}{System.out.print("r3 ");}static{System.out.print("r4 ");}}public class Test extends B{public static void main(String[] args){System.out.print("pre ");new Test();System.out.println("post ");}}

r1 r4 pre b1 b2 post

pre r1 r4 b1 b2 r2 r3 post

r1 r4 pre b1 b2 r3 r2 post

r1 r4 pre b1 b2 post r3 r2

Compilation fail

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A package is a collection of

Classes and Interfaces

Classes

Editing tools and Interfaces

Interfaces

Editing tools

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A method within a class is only accessible by classes that are defined within the same package as the class of the method. Which one of the following is used to enforce such restriction?

Declare the method with the keyword private.

Do not declare the method with any accessibility modifiers.

Declare the method with the keyword public.

Declare the method with the keyword protected.

Declare the method with the keyword public and private.

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What will be the output?public class Test{ public static void main(String[] args){ String value = "abc"; changeValue(value); System.out.println(value); } public static void changeValue(String a){ a = "xyz"; }}

Compilation fails

None of these

xyz

Compilation clean but no output

abc

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What will be the output?public class Test{static{int a = 5;}public static void main(String args[]){new Test().call();}void call(){this.a++;System.out.print(this.a);}}

5

0

6

Compile with error

Runtime Exception

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Determine Output:class MyClass{ static final int a = 20; static final void call(){ System.out.println("two"); } static{ System.out.println("one"); }}public class Test{ public static void main(String args[]){ System.out.println(MyClass.a); }}

one 20

one two

one

20

one two 20

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The object is created with new keyword

Depends on the code

None of these

At Compile-time

At run-time

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Choose the correct statementpublic class Circle{ private double radius; public Circle(double radius){ radius = radius; }}

The program has a compilation error because we cannot assign radius to radius.

The program does not compile because Circle does not have a default constructor.

The program has a compilation error because it does not have a main method.

The program will compile, but we cannot create an object of Circle with a specified radius. The object will always have radius 0.

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Consider the following two classes declared and defined in two different packages, what can be added in class B to form what considered a correct access to class A from main() method of class B?package subPackage;public class A { }package anotherPackage;// line 1public class B{public static void main(String[] args){// line 2}}1. At line1 add noting; At line2 add: new A();2. At line 1 add: import package.; at line 2 add : new subPackage.A();3. At line 1 add: import subPackage.; at line 2 add : new A();4. At line 1 add: import subPackage.A; at line 2 add : new A();

1 and 3

1 and 2

2 and 4

3 and 4

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What is the result of compiling and running the following code?class Base{ private Base(){ System.out.print("Base"); }}public class test extends Base{ public test(){ System.out.print("Derived"); } public static void main(String[] args){ new test(); }}

Derived

BaseDerived

Exception is thrown at runtime

Compilation Error

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