Java Programming Language

Declaration and Access Control in Java

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Evaluate your knowledge of Java declaration and access control with these multiple choice questions. Learn about the different access modifiers and how to declare variables and methods in Java. Take the quiz now! ➲ Declaration and Access Control in Java - Quiz

Q 1: 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){}

Q 2: 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

Q 3: What is the result of compiling and running the following code? 
public class Tester{
	static int x = 4;
	public Tester(){
		System.out.print(this.x); // line 1
		Tester();
	}
	public static void Tester(){ // line 2
		System.out.print(this.x); // 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 2 (constructors can't be static)
  • C Compile error at line 3 (static methods can't invoke this)
  • D Compile error at line 4 (invalid argument type for method main )

Q 4: 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)

Q 5: 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.

Q 6: The object is created with new keyword

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

Q 7: 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

Q 8: Determine output: 
public class InitDemo{
	static int i = demo();
	static{
                System.out.print(i);
        }
	InitDemo(){
		System.out.print("hello1");
	}
	public static void main(String... args){
                System.out.print("Hello2");
	}
 	static int demo(){
        	System.out.print("InsideDemo");
		return 10;
	}
}

  • A Compilation error.
  • B IllegalArgumentException is thrown at runtime.
  • C InsideDemo 10 Hello2
  • D Hello2 InsideDemo 10

Q 9: Which statements are most accurate regarding the following classes? 
class A{
        private int i;
        protected int j;
}

class B extends A{
        private int k;
        protected int m;
}

  • A An object of B contains data fields i, j, k, m.
  • B An object of B contains data fields j, k, m.
  • C An object of B contains data fields j, m.
  • D An object of B contains data fields k, m.

Q 10: A package is a collection of

  • A Classes
  • B Interfaces
  • C Editing tools
  • D Classes and Interfaces

Q 11: 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.

Q 12: 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.

Q 13: 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)

Q 14: You have the following code in a file called Test.java 
class Base{
      public static void main(String[] args){
            System.out.println("Hello");
      }
}
public class Test extends Base{}
What will happen if you try to compile and run this?

  • A It will fail to compile.
  • B Runtime error
  • C Compiles and runs with no output.
  • D Compiles and runs printing

Q 15: 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

Q 16: What will be the output for the below code? 
public class Test{
      static{
            int a = 5; 
      }

      public static void main(String[] args){
            System.out.println(a);
      }
}

  • A Compile with error
  • B 5
  • C 0
  • D Runtime Exception

Q 17: 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

Q 18: 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";
      }
}

  • A abc
  • B xyz
  • C Compilation fails
  • D Compilation clean but no output

Q 19: What is the output for the below code ? 
public class A{
      static{
            System.out.println("static");
      }

      {
            System.out.println("block");
      }

      public A(){
            System.out.println("A");
      }

      public static void main(String[] args){
            A a = new A();
      }
}

  • A A block static
  • B static block A
  • C static A
  • D None of these

Q 20: 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

Q 21: 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

Q 22: 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.

Q 23: What will be the output after compiling and running following program code? 
public class Test{
      static int a;
      public static void main(String[] args){
            System.out.println("one");
            call(1);
      }

      static void call(int a){
            this.a=10;
            System.out.println("two "+a);
      }
}

  • A one two 1
  • B one two 10
  • C one two 0
  • D Compile time error.

Q 24: 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.

Q 25: 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.