Constructor chaining in java using this and super Keywords

Constructor chaining example program in same class using this keyword.

1. package instanceofjava;
2. class ConstructorChaining{
3. int a,b 
4. ConstructorChaining(){
5. this(1,2);
6.  System.out.println("Default constructor");
7.  
8. } 
9.  
10. ConstructorChaining(int x , int y){
11.  
12. this(1,2,3); 
13. a=x;
14. b=y;
15.  System.out.println("Two argument constructor");
16.  
17. }
18.  
19. ConstructorChaining(int a , int b,int c){
20.  System.out.println("Three argument constructor")
21. } 
22.  
23. public static void main(String[] args){
24.  
25.  ConstructorChaining obj=new ConstructorChaining();
26.   System.out.println(obj.a);
27.   System.out.println(obj.b);
28.  
29. }
30. }

Output:

1. Three argument constructor
2. Two argument constructor
3. Default argument constructor
4. 1
5. 2

Constructor chaining example program in same class using this and super keywords.

1. package instanceofjava;
2. class SuperClass{
3.  
4. SuperClass(){
5. this(1);
6.  System.out.println("Super Class no-argument constructor");
7.  
8. } 
9.  
10. SuperClass(int x ){
11.  
12. this(1,"constructor chaining"); 
13. System.out.println("Super class one -argument constructor(int)");
14.  
15. }
16.  
17. SuperClass(int x , String str){
18.  System.out.println("Super class two-argument constructor(int, String)");
19. } 
20.  
21. }

1. package instanceofjava;
2. class SubClass extends SuperClass{
3. 
   
4. SubClass(){
5. this(1);
6.  System.out.println("Sub Class no-argument constructor");
7.  
8. } 
9.  
10. SubClass(int x ){
11.  
12. this("Constructor chaining"); 
13.  System.out.println("Sub class integer argument constructor");
14.  
15. }
16.  
17. ConstructorChaining(String str){
18. //here by default super() call will be there so it will call super class constructor
19.   System.out.println("Sub class String argument constructor");
20. } 
21.  
22. public static void main(String[] args){
23.  
24.  SubClass obj=new SubClass();
25.  
26.  
27. }
28. }

Output:

1. Super class two-argument constructor(int, String)
2. Super class one -argument constructor(int)
3. Super Class no-argument constructor
4. Sub class String argument constructor
5. Sub class String argument constructor
6. Sub class integer argument constructor