A narrowing primitive conversion with a constant expression is allowed in the assignment context. Two examples:

// literal
jshell> byte b = 42;
b ==> 42

// simple name that refers to a constant variable
jshell> class Test {
   ...> final int i = 42;
   ...> void test() {
   ...> byte b = i;
   ...> }
   ...> }
| created class Test

However, in JShell we observe the following erroneous behavior:

jshell> final int i = 42;
i ==> 42

jshell> byte b = i;
| Error:
| incompatible types: possible lossy conversion from int to byte
| byte b = i;
| ^