Why java is not fully object oriented?

Java is not pure object-oriented because it supports primitive like- int, byte, long, etc data types also,
this is the main reason why java is called not fully object-oriented or not pure object-oriented.

explanation:

public class Calculator
{
    public static void main(String args[])
      {
          int i, j,k;
           i= 10;
           j= 10;
           k=i+j;
           System.out.println(k);
//here you can see i, j and k is primitive type and used by java without any problem.
       }
}