Even for new Java developers, constructors are probably no big mystery. In essence, when you create an instance of a class, the constructor of this class is started. In the 6th part of Java Puzzlers series, we will see a case related to constructors.
01 02 03 04 05 06 07 08 09 10 | public class Puzzler { public Puzzler(){ System.out.println("Puzzler no arg constructor"); } public static void main(String[] args){ Puzzler puzzler = new Puzzler(); }} |
In the example above Puzzler() constructor will start and “Puzzler no arg constructor” will be printed to the screen. Now lets see a new example.
01 02 03 04 05 06 07 08 09 10 | public class Puzzler { public void Puzzler(){ System.out.println("Puzzler no arg constructor?"); } public static void main(String[] args){ Puzzler puzzler = new Puzzler(); }} |
As you can see we added a return value to the constructor of Puzzler and you may expect that “Puzzler no arg constructor?” will get printed but this is not right. When we add a return value to the constuctor, it stops being a constructor. So it won’t get started when a new instance is created.
Published on Java Code Geeks with permission by Sezin Karli, partner at our JCG program. See the original article here: java puzzlers from oca part 6 Opinions expressed by Java Code Geeks contributors are their own. |
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