Encapsulation in Java | Java Tutorial

Encapsulation is a mechanism of binding code and data together in a single unit. Let’s take an example of Capsule. Different powdered or liquid medicines are encapsulated inside a capsule. Likewise in encapsulation, all the methods and variables are wrapped together in a single class.

We will see detailed explanation with some example programs about Encapsulation in the post related to Encapsulation.

Let’s see how can we implement encapsulation. Set the instance variables private so that these private variables cannot be accessed directly by other classes. Set getter and setter methods of the class as public so that we can set and get the values of the fields.

Let’s see a sample program.

package encapsulationClass;

public class EncapsulationClassOne {
	
        // Variables declared as private
        // These private variables can only be accessed by public methods of class
	private int age;
	private String name;
	
        // getter method to access private variable
	public int getAge(){
		return age;
	}

	public String getName(){
		return name;
	}
	
        // setter method to access private variable
	public void setAge(int inputAge){
		age = inputAge;
	}
	
	public void setName(String inputName){
		name = inputName;
	}
	
}

package encapsulationClass;

public class EncapsulationClassTwo {
	
	public static void main(String [] args){
		
		EncapsulationClassOne obj = new EncapsulationClassOne();
                // Setting values of the variables
		obj.setAge(25);
		obj.setName("Rajkumar");
		
		System.out.println("My name is "+ obj.getName());
		System.out.println("My age is "+ obj.getAge());
		
	}

}

Output:

My name is Rajkumar
My age is 25

In the above example, you can find all the data member (variables) are declared as private. If the data member is private it means it can only be accessed within the same class. No other class can access these private variables of other class. To access these private variables from other classes, we used public getter and setter methods such as getAge(), getName(), setAge(), setName(). So, the data can be accessed by public methods when we can set the variables private and hide their implementation from other classes. This way we call encapsulation as data hiding.

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