[jira] [Commented] (GROOVY-11548) Could not inherit class and interface where class has a final method overridden by interface

["Paul King (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-11548?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17910517#comment-17910517 ] 

Paul King commented on GROOVY-11548:
------------------------------------

This is kind of by design (well, an implementation detail in Groovy 4). Groovy 5 compiles default interface methods natively. Groovy 4 emulates them with traits. So, your interface (because it has a default method) is converted to:
{code:groovy}
trait I0 {
    void func() { }
}
{code}
And the semantics of traits is to override rather than be a default. Groovy 5 lets you pick between traits and default methods in interfaces so you get the best of both worlds depending on your needs. The workaround in Groovy 4 is to write just that one interface in Java.

> Could not inherit class and interface where class has a final method overridden by interface
> --------------------------------------------------------------------------------------------
>
>                 Key: GROOVY-11548
>                 URL: https://issues.apache.org/jira/browse/GROOVY-11548
>             Project: Groovy
>          Issue Type: Bug
>          Components: Compiler
>    Affects Versions: 4.0.24
>         Environment: Tried on Linux and Windows, the same error.
>            Reporter: Xiaotian Ma
>            Priority: Major
>             Fix For: 5.0.0-alpha-11
>
>
> Compile following code.
> {code:groovy}
> class A {
>     final public void func() {
>     }
> }
> interface I0 {
>     public default void func() {
>     }
> }
> class B extends A implements I0 {
> }{code}
> Groovy 4.0.24:
> {code:java}
> A.groovy: -1: You are not allowed to override the final method func() from class 'A'.
> @ line -1, column -1.
> 1 error{code}
> Groovy 5.0.0-alpha-11: passed



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