Queueable interface in salesforce not allowed on inner class?

Question

I am trying to implement new Queueable interface of Winter 15 to allow chaining. But on one of my orgs it gives error as Invalid interface name specified. While same works properly on second org.

Both orgs are on Winter 15. API version is set to 32.0. Link - https://www.salesforce.com/us/developer/docs/apexcode/Content/apex_class_System_Queueable.htm

Any help. Code

public class AsyncExecutionExample implements System.Queueable {
    public void execute(QueueableContext context) {
        Account a = new Account(Name='Acme',Phone='(415) 555-1212');
        insert a;        
    }
}

Thanks, Ray

Answer 1

I found out what the issue was. For future reference -

implements Queueable is wrong as Q was capital. tried it with like implements queueable and it works fine.

Weird salesforce.

UPDATE : I contacted SF support and they mentioned this issue is on some specific orgs and they need to set some parameters in the backend for this to execute properly. More Weird

Answer 2

A common problem is a local class in an org (called Queueable in this case) hiding the platform's interface or class. (So the possibility here is that one org has the local class and the other doesn't. I'm assuming you are pushing the same class/inner class to both orgs.)

You can fix this (or eliminate it as the cause of the problem) by qualifying the reference like this System.Queueable.

For example this (contrived example; normally the problem class would be a separate class not an inner class):

public class A {

    public class Queueable {
    }

    public class B implements Queueable {
        public void execute(QueueableContext qc) {
        }
    }
}

fails to compile with:

Error: Compile Error: A.B: Invalid interface: Queueable at line 6 column 31

and can be fixed like this (qualifying the system class):

public class A {

    public class Queueable {
    }

    public class B implements System.Queueable {
        public void execute(QueueableContext qc) {
        }
    }
}

or like this (changing the name of the local class):

public class A {

    public class MyQueueable {
    }

    public class B implements Queueable {
        public void execute(QueueableContext qc) {
        }
    }
}