Declaration and Access Control in Java - Quiz

Q: Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code to compile:

public class Test{   
        public static void main(String args[]){
	        add(); 
		add(1);
		add(1, 2); 
	}

	// insert code here
}

A. void add(Integer... args){}
B. static void add(int... args, int y){}
C. static void add(int args...){}
D. static void add(int...args){}

Correct Option: D
Remarks:

Explanation: static void add(int...args){}

Q: Suppose a class has public visibility. In this class we define a protected method. Which of the following statements is correct?

A. This method is only accessible from inside the class itself and from inside all subclasses.
B. In a class, you cannot declare methods with a lower visibility than the visibility of the class in which it is defined.
C. From within protected methods you do not have access to public methods.
D. This method is accessible from within the class itself and from within all classes defined in the same package as the class itself.

Correct Option: D
Remarks:

Explanation: This method is accessible from within the class itself and from within all classes defined in the same package as the class itself.

Q: 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 1
	public 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

A. 1 and 2
B. 2 and 4
C. 3 and 4
D. 1 and 3

Correct Option: C
Remarks:

Explanation: 3 and 4

Q: 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?

A. Declare the method with the keyword public.
B. Declare the method with the keyword private.
C. Declare the method with the keyword protected.
D. Do not declare the method with any accessibility modifiers.

Correct Option: D
Remarks:

Explanation: Do not declare the method with any accessibility modifiers.

Q: Choose the correct statement

public class Circle{
      private double radius;  
      public Circle(double radius){
            radius = radius;
      }
}

A. The program has a compilation error because it does not have a main method.
B. The program will compile, but we cannot create an object of Circle with a specified radius. The object will always have radius 0.
C. The program has a compilation error because we cannot assign radius to radius.
D. The program does not compile because Circle does not have a default constructor.

Correct Option: B
Remarks:

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

Q: Choose the correct statement. Restriction on static methods are: I. They can only call other static methods.
I. They can only call other static methods.
II. They must only access static data.
III. They cannot refer this or super in any way.

A. Only (I)
B. (I) and (II)
C. (II) and (III)
D. (I), (II) and (III)

Correct Option: D
Remarks:

Explanation: (I), (II) and (III)

Q: Name the keyword that makes a variable belong to a class, rather than being defined for each instance of the class.

A. static
B. final
C. abstract
D. native

Correct Option: A
Remarks:

Explanation: static

Q: 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);
      }
}

A. one
B. one two
C. one two 20
D. one 20

Correct Option: D
Remarks:

Explanation: one 20

Q: What will be the output for the below code?

static public class Test{
      public static void main(String[] args){
            char c = 'a';

            switch(c){
                  case 65 : System.out.println("one");break;
		  case 'a': System.out.println("two");break;
		  case 3  : System.out.println("three");
            }	
      }
}

A. one
B. two
C. Compile error - char can't be permitted in switch statement.
D. Compile error - Illegal modifier for the class Test; only public, abstract & final are permitted.

Correct Option: D
Remarks:

Explanation: Compile error - Illegal modifier for the class Test; only public, abstract & final are permitted.

Q: What can directly access and change the value of the variable qusNo?

package com.mypackage;

public class Test{
    private int qusNo = 100;
}

A. Only the Test class.
B. Any class.
C. Any class in com.mypackage package.
D. Any class that extends Test.

Correct Option: A
Remarks:

Explanation: Only the Test class.

Declaration and Access Control in Java - Quiz

Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code to compile:
public class Test{ public static void main(String args[]){ add(); add(1); add(1, 2); } // insert code here }

Suppose a class has public visibility. In this class we define a protected method. Which of the following statements is correct?

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?

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

Choose the correct statement. Restriction on static methods are: I. They can only call other static methods.
I. They can only call other static methods.
II. They must only access static data.
III. They cannot refer this or super in any way.

Name the keyword that makes a variable belong to a class, rather than being defined for each instance of the class.

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); } }

What will be the output for the below code?
static public class Test{ public static void main(String[] args){ char c = 'a'; switch(c){ case 65 : System.out.println("one");break; case 'a': System.out.println("two");break; case 3 : System.out.println("three"); } } }

What can directly access and change the value of the variable qusNo?
package com.mypackage; public class Test{ private int qusNo = 100; }

Declaration and Access Control in Java - Quiz

Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code to compile: public class Test{ public static void main(String args[]){ add(); add(1); add(1, 2); } // insert code here }

Suppose a class has public visibility. In this class we define a protected method. Which of the following statements is correct?

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?

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

Choose the correct statement. Restriction on static methods are: I. They can only call other static methods. I. They can only call other static methods.II. They must only access static data.III. They cannot refer this or super in any way.

Name the keyword that makes a variable belong to a class, rather than being defined for each instance of the class.

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); } }

What will be the output for the below code? static public class Test{ public static void main(String[] args){ char c = 'a'; switch(c){ case 65 : System.out.println("one");break; case 'a': System.out.println("two");break; case 3 : System.out.println("three"); } } }

What can directly access and change the value of the variable qusNo? package com.mypackage; public class Test{ private int qusNo = 100; }

Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code to compile:
public class Test{ public static void main(String args[]){ add(); add(1); add(1, 2); } // insert code here }

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

Choose the correct statement. Restriction on static methods are: I. They can only call other static methods.
I. They can only call other static methods.
II. They must only access static data.
III. They cannot refer this or super in any way.

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); } }

What will be the output for the below code?
static public class Test{ public static void main(String[] args){ char c = 'a'; switch(c){ case 65 : System.out.println("one");break; case 'a': System.out.println("two");break; case 3 : System.out.println("three"); } } }

What can directly access and change the value of the variable qusNo?
package com.mypackage; public class Test{ private int qusNo = 100; }