The phrase signifies a specific error state encountered within the Android operating system’s execution environment. It commonly arises when attempting to retrieve or utilize data associated with an `Executor`, a component responsible for managing and executing asynchronous tasks, but the key required to access that data is missing or invalid. This situation typically occurs during parallel processing or background operations when identifiers used for referencing results or state between threads are mishandled.
Understanding and addressing this issue is crucial for maintaining application stability and data integrity. Its presence indicates a potential flaw in the application’s logic, specifically concerning the management of concurrency and data association across different threads. Historically, such problems were more prevalent due to the complexities of manual thread management. Modern concurrency APIs aim to mitigate these risks, but proper implementation is still essential to avoid the recurrence of this specific error.