JShell: Redeclared variable should be reset

A DESCRIPTION OF THE PROBLEM :
The result of line 13 of the test of the redeclared variable ‘a’ that previously contained a non-null value and compare against the results of lines 4 and 19.
 
My current thinking is that lines 10 and 16 are both setting a to null, so the instanceof test on subsequent lines (13 and 19) should evaluate to false in both cases


1. jshell> Integer a;
2. a ==> null
3.
4. jshell> a instanceof Integer;
5. $2 ==> false
6.
7. jshell> a = 1;
8. a ==> 1
9.
10. jshell> Integer a;
11. a ==> null
12.
13. jshell> a instanceof Integer;
14. $5 ==> true
15.
16. jshell> a = null;
17. a ==> null
18.
19. jshell> a instanceof Integer;
20. $7 ==> false


FREQUENCY : always