Encapsulation
Encapsulation is the process of wrapping or binding all the functions and data together into a single unit. So we can hide the implementation of the code from the user by using access specifiers. We can make private member variables and have public getters to read data from the variable and setters to write data to the variable, so likewise we can control the access to those variables. Code: public class TestEncapsulation{ public static void main(String args[]){ Circle c1=new Circle(7.0); System.out.println("Radius of the circle is:"+c1.getRadius()); System.out.println("Perimeter of the circle is:"+c1.getPerimeter()); c1.setRadius(14.0); System.out.println("Radius of the circle is:"+c1.getRadius()); System.out.println("Perimeter of the circle is:"+c1.getPerimeter()); } } class Circle{ private double radius; private double perimeter; Circle(double radius){ this.radius=radius; setPerimeter(); } public void setRadiu...