public class ConcurrentModificationException extends RuntimeException
For example, it is not generally permissible for one thread to modify a Collection while another thread is iterating over it. In general, the results of the iteration are undefined under these circumstances. Some Iterator implementations (including those of all the general purpose collection implementations provided by the JRE) may choose to throw this exception if this behavior is detected. Iterators that do this are known as fail-fast iterators, as they fail quickly and cleanly, rather that risking arbitrary, non-deterministic behavior at an undetermined time in the future.
Note that this exception does not always indicate that an object has been concurrently modified by a different thread. If a single thread issues a sequence of method invocations that violates the contract of an object, the object may throw this exception. For example, if a thread modifies a collection directly while it is iterating over the collection with a fail-fast iterator, the iterator will throw this exception.
Note that fail-fast behavior cannot be guaranteed as it is, generally
speaking, impossible to make any hard guarantees in the presence of
unsynchronized concurrent modification. Fail-fast operations
ConcurrentModificationException on a best-effort basis.
Therefore, it would be wrong to write a program that depended on this
exception for its correctness:
should be used only to detect bugs.
|Constructor and Description|
Constructs a ConcurrentModificationException with no detail message.
Constructs a new exception with the specified detail message and cause.
Constructs a new exception with the specified cause and a detail message of
addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString
public ConcurrentModificationException(String message)
ConcurrentModificationExceptionwith the specified detail message.
message- the detail message pertaining to this exception.
public ConcurrentModificationException(Throwable cause)
(cause==null ? null : cause.toString())(which typically contains the class and detail message of
cause- the cause (which is saved for later retrieval by the
nullvalue is permitted, and indicates that the cause is nonexistent or unknown.)
Note that the detail message associated with
not automatically incorporated in this exception's detail
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, 2017, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.