Why am i getting error in that code ?why can't we do like that?

Question

https://code.sololearn.com/coiADOd6hFKh/?ref=app

Answer 1

Just delete obj.a; at line 5.
If you write this without any statement like:
Obj.a=5;
The program will get error

Answer 2

delete at line 5, Sololearn counts lines incorrect
//obj.a;
System .out.println (obj.a);

obj.a do nothing, it is not method nor assignment