Java Inheritance Part 1: Inheriting Public Members

Inheritance:

Inheritance is a process where one class acquires the properties (variable and methods) of another class.

Importance:

• For code reusability.
• For method overloading.
• Implement parent-child relationship.

Code:

1. // Base class  
2.   
3. public class StudentI {  
4.       
5.     int id;  
6.     String name;  
7.     String dept;  
8.       
9.     public void dispInfo() {  
10.         System.out.println("Id : "+id);  
11.         System.out.println("Name : "+name);  
12.         System.out.println("Department : "+dept);  
13.     }  
14.   
15. }  
16.   
17. // Derived class  
18.   
19. public class TeacherI extends StudentI { //inherit class studenti  
20.       
21.     int age;  
22.       
23.     public void disp() {  
24.         dispInfo();  
25.         System.out.println("Age : "+age);  
26.     }  
27.   
28. }  
29.   
30. // Main class  
31.   
32.   
33. public class InheritanceDemo {  
34.   
35.     public static void main(String[] args) {  
36.         // TODO Auto-generated method stub  
37.           
38.         StudentI s1=new StudentI();  
39.         s1.id=1001;  
40.         s1.name="Sujan Hasan";  
41.         s1.dept="CSE";  
42.         s1.dispInfo();  
43.         System.out.println();  
44.           
45.         StudentI s2=new StudentI();  
46.         s2.id=1002;  
47.         s2.name="Shakil Sorker";  
48.         s2.dept="CSE";  
49.         s2.dispInfo();  
50.         System.out.println();  
51.           
52.         TeacherI t1=new TeacherI();  
53.         t1.id=7001;  
54.         t1.name="Alamgir Hossain";  
55.         t1.dept="CSE";  
56.         t1.age=30;  
57.         t1.disp();  
58.         System.out.println();  
59.           
60.         TeacherI t2=new TeacherI();  
61.         t2.id=7003;  
62.         t2.name="Shamol Pal";  
63.         t2.dept="CSE";  
64.         t2.age=37;  
65.         t2.disp();  
66.         System.out.println();  
67.           
68.   
69.     }  
70.   
71. }