Java Encapsulation

Java Encapsulation

Encapsulation, one of the four fundamental OOP concepts, is the mechanism of wrapping the data (variables) and code acting on the data (methods) together as a single unit.

The main purpose of encapsulation is to ensure data hiding. To achieve this, you must:

1. Declare the variables of a class as private.
2. Provide public "setter" and "getter" methods to modify and view the variables' values.

Why Encapsulation?

• Better control of class attributes and methods: You can make attributes read-only (if you only provide a getter) or write-only (if you only provide a setter).
• Increased flexibility and maintainability: The programmer can change the internal implementation of the class without affecting the code that uses it.
• Data Hiding: It prevents direct access to the data members (attributes) of a class. This is a security feature that protects the data from accidental modification.

Getters and Setters

To access the private variables, we use public "get" and "set" methods.

• The getter method returns the variable value.
• The setter method sets the variable value.

By convention, getters start with get and setters start with set, followed by the variable name (e.g., getName(), setName()).

public class Person {
  private String name; // private = restricted access

  // Getter
  public String getName() {
    return name;
  }
  // Setter
  public void setName(String newName) {
    // We can add validation logic here
    if (newName != null && !newName.isEmpty()) {
      this.name = newName;
    }
  }
}
public class Main {
  public static void main(String[] args) {
    Person myObj = new Person();
    // myObj.name = "John"; // This would cause an error
    myObj.setName("John"); // Set the value of the name variable to "John"
    System.out.println(myObj.getName());
  }
}

In the setName method, we added a simple validation check. This is a key benefit of encapsulation: you control how your data is set, preventing invalid data from being assigned to your object's attributes.