V - The result type of the I/O operationA - The type of the object attached to the I/O operationpublic interface CompletionHandler<V,A>
 The asynchronous channels defined in this package allow a completion
 handler to be specified to consume the result of an asynchronous operation.
 The completed method is invoked when the I/O operation
 completes successfully. The failed method is invoked if the
 I/O operations fails. The implementations of these methods should complete
 in a timely manner so as to avoid keeping the invoking thread from dispatching
 to other completion handlers.
| Modifier and Type | Method and Description | 
|---|---|
| void | completed(V result,
         A attachment)Invoked when an operation has completed. | 
| void | failed(Throwable exc,
      A attachment)Invoked when an operation fails. | 
 Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
 Copyright © 1993, 2025, Oracle and/or its affiliates.  All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.