Declaration and Access Control in Java - Quiz

Q: 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();
        }
}

A. BaseDerived
B. Derived
C. Exception is thrown at runtime
D. Compilation Error

Correct Option: D
Remarks:

Explanation: Compilation Error

Q: What is the result of compiling and running the following code?

public class Tester{
	static int x = 4;
	int y = 9;  	
	public Tester(){
		System.out.print(this.x); // line 1
		printVariables();
	}
	public static void printVariables(){
		System.out.print(x); // line 2
		System.out.print(y); // line 3
	}
	public static void main(String... args) { // line 4
		new Tester();
	}
}

A. Compile error at line 1 (static x must be only accessed inside static methods)
B. Compile error at line 3 (static methods can't make reference to non-static variables)
C. Compile error at line 4 (invalid argument type for method main)
D. Compile error at line 2 (must access x by writing Tester.x)

Correct Option: B
Remarks:

Explanation: Compile error at line 3 (static methods can't make reference to non-static variables)

Q: The object is created with new keyword

A. At Compile-time
B. At run-time
C. Depends on the code
D. None of these

Correct Option: B
Remarks:

Explanation: At run-time

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: 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: 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);
	}
}

A. Compile with error
B. Runtime Exception
C. 5
D. 6

Correct Option: A
Remarks:

Explanation: Compile with error

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: 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 ");
	}
}

A. r1 r4 pre b1 b2 post
B. pre r1 r4 b1 b2 r2 r3 post
C. r1 r4 pre b1 b2 r3 r2 post
D. r1 r4 pre b1 b2 post r3 r2

Correct Option: C
Remarks:

Explanation: r1 r4 pre b1 b2 r3 r2 post

Q: What will be the output after the following program is compiled and executed?

public class Test{
      public static void main(String args[]){
            int x = 10;
	    x = myMethod(x--);
	    System.out.print(x);
      }

      static int myMethod(final int x){
            return x--;
      }
}

A. The will compile successfully and display 9 as output.
B. The program will lead to compilation error.
C. The program will lead to runtime error.
D. The program will compile successfully and display 10 as output.

Correct Option: B
Remarks:

Explanation: The program will lead to compilation error.

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

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(); } }

The object is created with new keyword

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

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); } }

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 after the following program is compiled and executed?
public class Test{ public static void main(String args[]){ int x = 10; x = myMethod(x--); System.out.print(x); } static int myMethod(final int x){ return x--; } }

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

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(); } }

The object is created with new keyword

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

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); } }

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 after the following program is compiled and executed? public class Test{ public static void main(String args[]){ int x = 10; x = myMethod(x--); System.out.print(x); } static int myMethod(final int x){ return x--; } }

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

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(); } }

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

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); } }

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 after the following program is compiled and executed?
public class Test{ public static void main(String args[]){ int x = 10; x = myMethod(x--); System.out.print(x); } static int myMethod(final int x){ return x--; } }

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