@AroundConstruct method returning Object works only if it's private

[jmartisk]

InterceptorGenerator incorrectly assumes that return type from an @AroundConstruct method is void, but the specification allows Object too (https://docs.oracle.com/javaee/7/api/javax/interceptor/AroundConstruct.html).

When the method is private, it will work because InterceptorGenerator will use a reflection fallback and find the method to invoke by name and param types only (so the return type doesn't matter): https://github.com/quarkusio/quarkus/blob/0.12.0/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/InterceptorGenerator.java#L245

[mkouba]

Well, it is allowed and it's IMHO quite useless and misleading. But the truth is that in theory it should be possible to intercept both AroundConstruct and AroundInvoke with one method and so we should fix it.