Java quiz 01: Passing parameters to constructors

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I would emphasize that understanding constructors helps you by initializing instance variables. In the following code, I try to make that concept clear. I use a trick to make it difficult to guess the result if you don’t understand the constructor block.

Java quiz 1: Passing parameters to constructors

Level: Normal

What is the output of the following program?

public class Student
  String name = "Emily";
  int age = 20;
  Student(String name, int age)
  { = name;
    this.age = 22;
  public static void main(String[] args)
    Student st = new Student("Oliver", 21);
    System.out.print(", " + st.age);
Author: Sar Maroof

Select the correct answer.

Answer explanation

  1. By creating the object st using the constructor of the Student class, we need to pass two parameters to the constructor.
  2. Inside the constructor we assign the name parameter to the class variable name by using the statement = name;. Therefore the name is Oliver.
  3. In the constructor the age parameter is not assigned to the variable age. No matter which age you pass to the constructor, the value 22 is assigned to the age. See the statement this.age = 22;.

The right answer is a. Oliver, 22

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Please, leave your questions, feedback and suggestions in the comments below! offers a practical method to learn and improve your Java skills. It avoids unnecessary long boring theoretical explanations, but it uses many exercises and quizzes.

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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