I was trying out the superbadge of Data Integration specialist and implemented the inner class QueueablePMSCall as expected. The class was declared as:
private class QueueablePMSCall implements Queueable{
//code inside
}
However, I received error that "Could not find an inner class named 'QueueablePMSCall' that implements System.Queueable and Database.AllowsCallouts."
I have 2 queries here:
- The issue resolved when I used System.Queueable instead of Queueable. Is this due to trailhead engines's testing code. Also, which is advisable to be used?
- Why is Database.AllowsCallouts required to be implemented for queueable apex? Please provide any documentation mentioning use of this interface other than in Batch Apex.