Hi Could you please explain why is this output public class

Hi!

Could you please explain why is this output?

public class TestTables
{
   public static void main(String [] args)
   {
      Table kitchen = new Table();
      Table den = new Table();
      Table study = new Table();
      Table library = study;

      kitchen.chairs = 2;
      library.chairs = 1;

      study.chairs += 10;
      library.chairs += 20;

      study.print();
      library.print();
   }
}

class Table
{
   int chairs = 5;

   public void print()
   {
      System.out.println(chairs);
   }
}

Answer: 31 31

Solution

1.) Table study = new Table();
This line allocates memory for a Table object, and that location is pointed to by \'study\'.
Right now, chairs variable of the object stores 1.

2 .) Table library= study;
This line would Not create a new object. Instead, it would make library instance point to the same location as study .
So now, library and study are referencing the same object.

3.) library.chairs=1;
It changes the value of chairs variable in the object to 1.

4.) study.chairs += 10;
library.chairs += 20;
It increments the value of chairs variable in the object, first by 10 and then by 20. 1+10+20. Hence, 31.