Interesting...I confirm that this, which I have done in the past (well, something like this) DOES compile:
jshell> enum Season {
...> WINTER {
...> public void printHours() { System. out .println("9am-3pm");}
...> }, SPRING {
...> public void printHours() { System. out .println("9am-4pm");}
...> }, SUMMER, FALL {
...> public void printHours() { System. out .println("9am-5pm");}
...> };
...> public void printHours() { System.out.println("Did the Poster lie or get confused??");}
...> }
| created enum Season
While I seem to get the same error as you did when I try what the poster attested that they saw working:
jshell> enum Season {
...> WINTER {
...> public void printHours() { System. out .println("9am-3pm");}
...> }, SPRING {
...> public void printHours() { System. out .println("9am-5pm");}
...> }, SUMMER, FALL {
...> public void printHours() { System. out .println("9am-5pm");}
...> };
...> public abstract void printHours() ;
...> }
| Error:
| Season is abstract; cannot be instantiated
| }, SUMMER, FALL {
| ^
I am in JShell,
Java SE 17 OpenJDK version there if it matters, but I suspect it is more likely that the OP erred or got confused?