Answer:see explanation
Explanation:
Hello, the solution is the following:
in a file named Shelf.java :
public class Shelf{
    int length;
    int breadth;
    int capacity;
    boolean occupied;
    Shelf(int length,int breadth, int capacity){
        this.length = length;
        this.breadth = breadth;
        this.capacity = capacity;
        this.occupied = false;
    }
    
    //set methods
    public void setLength(int length){
        this.length = length;
    }
    public void setBreadth(int breadth){
        this.breadth = breadth;
    }
    public void setCapacity(int capacity){
        this.capacity = capacity;
    }
    public void setOccupied(boolean occupied){
        this.occupied = occupied;
    }
    
    //get methods
    public int getLength(){
        return this.length;
    }
    public int getBreadth(){
        return this.breadth;
    }
    public int getCapacity(){
        return this.capacity;
    }
    public boolean getOccupied(){
        return this.occupied;
    }
    
    //tostring method
    
    public String toString(){//overriding the toString() method  
  return "Shelf: \n"+" length: "+Integer.toString(this.length)+" breadth: "+Integer.toString(this.breadth)+" capacity: "+Integer.toString(this.capacity)+" occupied: "+Boolean.toString(this.occupied); 
 }  
}
in another file named ShelfCheck.java
public class ShelfCheck {
  public static void main(String[] args) {
    Shelf s1=new Shelf(100,150,300);
    Shelf s2=new Shelf(200,200,234);  
    Shelf s3=new Shelf(300,222,543);  
    Shelf s4=new Shelf(400,434,654);
    System.out.println(s1);
    System.out.println(s2);
    System.out.println(s3);
    System.out.println(s4);
    s4.setLength(5);
    System.out.println(s4);
    s2.setBreadth(2);
    System.out.println(s2);
    s3.setCapacity(1);
    System.out.println(s3);
    s1.setOccupied(true);
    System.out.println(s1);
  }
}
OUTPUT:
Shelf: 
 length: 100 breadth: 150 capacity: 300 occupied: false
Shelf: 
 length: 200 breadth: 200 capacity: 234 occupied: false
Shelf: 
 length: 300 breadth: 222 capacity: 543 occupied: false
Shelf: 
 length: 400 breadth: 434 capacity: 654 occupied: false
Shelf: 
 length: 5 breadth: 434 capacity: 654 occupied: false
Shelf: 
 length: 200 breadth: 2 capacity: 234 occupied: false
Shelf: 
 length: 300 breadth: 222 capacity: 1 occupied: false
Shelf: 
 length: 100 breadth: 150 capacity: 300 occupied: true