sadstephen Posts - Answer Overflow

sadstephen

•Created by sadstephen on 1/26/2025 in #java-help

Why does creating a subclass of some Exception, throws this error?

Custom exceptions are supposed to be caught if occurs, not intentionally thrown.

jshell> class WrongInputException extends Exception {
   ...>     public String toString() {
   ...>        return "ERROR!!";
   ...>    }
   ...> }

jshell> try {
   ...>     ;
   ...> }
   ...> catch (ArithmeticException a) {
   ...>     ;
   ...> }            // <-------   compiles fine here

jshell> try {
   ...>     ;    // if I use throw new WrongInputException() it would have compiled perfectly
   ...> }
   ...> catch (WrongInputException a) {
   ...>     ;
   ...> }
|  Error:
|  exception WrongInputException is never thrown in body of corresponding try statement
|  catch (WrongInputException a) {
|  ^------------------------------...

jshell> class WrongInputException extends Exception {
   ...>     public String toString() {
   ...>        return "ERROR!!";
   ...>    }
   ...> }

jshell> try {
   ...>     ;
   ...> }
   ...> catch (ArithmeticException a) {
   ...>     ;
   ...> }            // <-------   compiles fine here

jshell> try {
   ...>     ;    // if I use throw new WrongInputException() it would have compiled perfectly
   ...> }
   ...> catch (WrongInputException a) {
   ...>     ;
   ...> }
|  Error:
|  exception WrongInputException is never thrown in body of corresponding try statement
|  catch (WrongInputException a) {
|  ^------------------------------...

9 replies

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•Created by sadstephen on 1/19/2025 in #java-help

Can I make a superclass's variable static final in subclass?

abstract class User {
       String about;
}
class Bots extend User {
        final static String about = "Bots are not humans"; // I think this replaces Superclass 's instance variable about
}

abstract class User {
       String about;
}
class Bots extend User {
        final static String about = "Bots are not humans"; // I think this replaces Superclass 's instance variable about
}

21 replies

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