» » Encapsulation in java with example program

What is meant by encapsulation in java?
  • Binding the data with its related functionalities known as encapsulation
  • Here data means variables and functionalities means methods.
  • So keeping the variable and related methods in one place.
  • That place is "class". class is the base for encapsulation.
  • Lets see example program on encapsulation, how the variables and methods defined in a class



What is encapsulation in object oriented programming?
 
Basic java example program on data encapsulation:
  1. package com.instanceofjava;
  2.  
  3. public class EncapsulationDemo {
  4.  
  5.   String name;
  6.   int rno;
  7.   String address;
  8.  
  9. public String getName() {
  10.        return name;
  11.  }
  12.  
  13. public void setName(String name) {
  14.         this.name = name;

  15. public int getRno() {
  16.        return rno;
  17. }
  18.  
  19. public void setRno(int rno) {
  20.      this.rno = rno;
  21. }
  22.  
  23. public String getAddress() {
  24.         return address;
  25. }
  26.  
  27.  public void setAddress(String address) {
  28.     this.address = address;
  29. }
  30.  
  31. public void showInfo(){
  32.  
  33.       System.out.println("Name: "+getName());
  34.       System.out.println("R.No: "+getRno());
  35.       System.out.println("Name: "+getAddress());
  36.  
  37.     }
  38. }


Class:

  • The above example program shows how the variables and methods will be there in a class.
  • So class is the base for encapsulation
  • class is user defined data type in java means by using class we can structure our own programs.
  • Lest see a example program on class.

  1. package com.instanceofjava;
  2.  
  3. public class ClassDemo {
  4.  
  5.     //variables of a class
  6.    String empName;
  7.    int empId;
  8.    String Designation;
  9.  
  10.  //getter and setter methods for variables 
  11.  //by using these methods we can set the value to the variable and gat the value from the
  12.  //variables
  13.  
  14.  public String getEmpName() {
  15.         return empName;
  16. }
  17.  
  18.  public void setEmpName(String empName) {
  19.       this.empName = empName;
  20. }
  21.  
  22. public int getEmpId() {
  23.        return empId;
  24. }
  25.  
  26. public void setEmpId(int empId) {
  27.         this.empId = empId;
  28. }

  29. public String getDesignation() {
  30.         return Designation;
  31. }
  32.  
  33.  public void setDesignation(String designation) {
  34.         Designation = designation;
  35. }

  36. }

Object:

  • Instance of class is known as object.
  • Instance means dynamic memory allocation. So dynamic memory allocation to class is called object.
  • By using "new" keyword the object will be created dynamically.
  • Class is a template. By using object we will get memory for all variables so that we can use them.

  • We can create number of objects for one class based on our requirements.
  • Below an example program on class and object.


  1. package com.instanceofjava; 
  2.  
  3. public class User {
  4.  
  5.    String Name;
  6.     int Id;
  7.     String address;
  8.  
  9.  public String getName() {
  10.      return Name;
  11. }
  12.  
  13. public void setName(String name) {
  14.         Name = name;
  15. }
  16.  
  17. public int getId() {
  18.       return Id;
  19. }
  20.  
  21. public void setId(int id) {
  22.        Id = id;
  23. }
  24.  
  25. public String getAddress() {
  26.         return address;
  27. }
  28.  
  29. public void setAddress(String address) {
  30.         this.address = address;
  31. }
  32.  
  33. public static void main(String [] args){
  34.  
  35.        User obj= new User();
  36.  
  37.         obj.setName("sai");
  38.         obj.setId(1);
  39.         obj.setAddress("xyz");
  40.  
  41.         System.out.println(obj.getName());
  42.         System.out.println(obj.getId());
  43.         System.out.println(obj.getAddress());
  44.  
  45.     }
  46. }

Output:

  1. sai
  2. 1
  3. xyz


encapsulation in java

Instance Of Java

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