Practice Declaration And Access Control Multiple Choice Questions with Answers Quiz-1

Q.1.

The object is created with new keyword

At Compile-time
At run-time
Depends on the code
None of these

Q.2.

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

package com.mypackage;

public class Test{
    private int qusNo = 100;
}

Only the Test class.
Any class.
Any class in com.mypackage package.
Any class that extends Test.
None of these

Q.3.

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 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 2
2 and 4
3 and 4
1 and 3

Q.4.

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;
	}
}

Compilation error.
IllegalArgumentException is thrown at runtime.
InsideDemo 10 Hello2
Hello2 InsideDemo 10
InsideDemo 10 Hello2 hello1

Explanation

Q.5.

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;
}

An object of B contains data fields i, j, k, m.
An object of B contains data fields j, k, m.
An object of B contains data fields j, m.
An object of B contains data fields k, m.

Q.6.

A package is a collection of

Classes
Interfaces
Editing tools
Classes and Interfaces
Editing tools and Interfaces

Q.7.

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

Explanation

Q.8.

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");
            }	
      }
}

one
two
Compile error - char can't be permitted in switch statement.
Compile error - Illegal modifier for the class Test; only public, abstract & final are permitted.
None of these

Explanation

Q.9.

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);
      }
}

one two 1
one two 10
one two 0
Compile time error.
None of these

Explanation

Q.10.

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--;
      }
}

The will compile successfully and display 9 as output.
The program will lead to compilation error.
The program will lead to runtime error.
The program will compile successfully and display 10 as output.
None of these

Explanation

Q.11.

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
one two
one two 20
20
one 20

Q.12.

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 block static
static block A
static A
A
None of these

Explanation

Q.13.

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";
      }
}

abc
xyz
Compilation fails
Compilation clean but no output
None of these

Explanation

Q.14.

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

static
final
abstract
native
volatile

Q.15.

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);
      }
}

Compile with error
5
0
Runtime Exception
None of these

Explanation

Q.16.

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 public.
Declare the method with the keyword private.
Declare the method with the keyword protected.
Do not declare the method with any accessibility modifiers.
Declare the method with the keyword public and private.

Q.17.

Choose the correct statement

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

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.
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.

Q.18.

Choose the correct statement. Restriction on static methods are: 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.

Only (I)
(I) and (II)
(II) and (III)
Only (III)
(I), (II) and (III)

Q.19.

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?

It will fail to compile.
Runtime error
Compiles and runs with no output.
Compiles and runs printing

Explanation

Q.20.

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);
	}
}

Compile with error
Runtime Exception
5
6
0

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