Answer:
Java program is given below. You can get .class after you execute java programs, You can attach those files along with .java classes given , Those .class files are generated ones. 
Step-by-step explanation:
//Rectangle.java class 
 
public class Rectangle { 
 
private int x; 
 
private int y; 
 
private int width; 
 
private int height; 
 
// constructs a new Rectangle with the given x,y, width, and height 
 
public Rectangle(int x, int y, int w, int h) 
 
{ 
 
this.x=x; 
 
this.y=y; 
 
this.width=w; 
 
this.height=h; 
 
} 
 
// returns the fields' values 
 
public int getX() 
 
{ 
 
return x; 
 
} 
 
public int getY() 
 
{ 
 
return y; 
 
} 
 
public int getWidth() 
 
{ 
 
return width; 
 
} 
 
public int getHeight() 
 
{ 
 
return height; 
 
} 
 
// returns a string such as “Coordinate is (5,12) and dimension is 4x8” where 4 is width and 8 is height. public String toString() 
 
public String toString() 
 
{ 
 
String str=""; 
 
//add x coordidate , y-coordinate , width, height and area to str and return 
 
str+="Coordinate is ("+x+","+y+")"; 
 
str+=" and dimension is : "+width+"x"+height; 
 
str+=" Area is "+(width*height); 
 
return str; 
 
} 
 
public void changeSize(int w,int h) 
 
{ 
 
width=w; 
 
height=h; 
 
} 
 
} 
 
====================== 
 
//main.java 
 
class Main { 
 
public static void main(String[] args) { 
 
//System.out.println("Hello world!"); 
 
//create an object of class Rectangle 
 
Rectangle rect=new Rectangle(5,12,4,8); 
 
//print info of rect using toString method 
 
System.out.println(rect.toString()); 
 
//chamge width and height 
 
rect.changeSize(3,10); 
 
//print info of rect using toString method 
 
System.out.println(rect.toString()); 
 
} 
 
} 
 
========================================================================================== 
 
//Output 
 
Coordinate is (5,12) and dimension is : 4x8 Area is 32 
Coordinate is (5,12) and dimension is : 3x10 Area is 30 
 
========================================================================================