Default constructor in Java

Like C++, Java automatically creates default constructor if there is no default or parameterized constructor written by user, and (like C++) the default constructor automatically calls parent default constructor. But unlike C++, default constructor in Java initializes member data variable to default values (numeric values are initialized as 0, booleans are initialized as false and references are initialized as null).

For example, output of the below program is

0
null
false
0
0.0



filter_none

edit
close

play_arrow

link
brightness_4
code

// Main.java
class Test {
   int i;
   Test t;
   boolean b;
   byte bt;
   float ft;
}
  
public class Main {
    public static void main(String args[]) {
      Test t = new Test(); // default constructor is called.
      System.out.println(t.i);
      System.out.println(t.t);
      System.out.println(t.b);
      System.out.println(t.bt);
      System.out.println(t.ft);
    }
}

chevron_right


Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

References:
http://leepoint.net/notes-java/oop/constructors/constructor.html



My Personal Notes arrow_drop_up


Article Tags :
Practice Tags :


12


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.