Java quiz 22: Handling inner classes

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This code shows handeling inner classes in Java. You have to store the whole code
in one file with the name Outer.

Java quiz 22: Handling inner classes

Level: Normal

What happens if the following code is compiled and run?

public class Outer
  int x;
  int y;
  Outer(int x, int y)
    x += 2;
    y += 3;
    System.out.print("x" + this.x);
    System.out.print(", ");
    System.out.print("y" + this.y);
    System.out.print(", ");
  class Inner
      x += 3;
      y += 2;
      System.out.print("x" + x);
      System.out.print(", ");
      System.out.print("y" + y);
  public static void main(String[] args)
    new Outer(4, 5).new Inner();
Author: Sar Maroof

Select the correct answer.

Answer explanation

  1. The statement new Outer(4, 5) calls the two argument constructor of the Outer class.
  2. The statement x += 2; and y += 3; incremnts the value of the parameters x and y by 2 and 3 respectively.
  3. The statement System.out.print(“x” + this.x + “, ” + “y” + this.y + “, “); writes the values of the instance variables x and y to the standard output, which are respectively 0 and 0. Therefore the statement writes x0, y0 to the standard output.
  4. The statments x += 3; and y += 2; increments the values of the instance variables x and y by 3 and 2 respectively.
  5. The statement System.out.print(“x” + x + “, ” + “y” + y); writes the values of the instance variables x and y to the standard output, So, it writes x3, y2 to the standard output.

The correct answer is: d.


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Sar Maroof is graduated from HBO Amsterdam "higher professional education". He is a professional computer programming teacher, gives master classes and publishes technical articles. His experience with developing software started from 2001 and he has worked as a software developer for several big as well as small companies and later as a freelancer. He is the author of Java quizmaster and Build a Java application in 7 days.

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