- All Implemented Interfaces:
Serializable
- Direct Known Subclasses:
DirectoryIteratorException
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
throw ConcurrentModificationException
on a best-effort basis.
Therefore, it would be wrong to write a program that depended on this
exception for its correctness: ConcurrentModificationException
should be used only to detect bugs.
- Since:
- 1.2
- See Also:
Collection
,Iterator
,Spliterator
,ListIterator
,Vector
,LinkedList
,HashSet
,Hashtable
,TreeMap
,AbstractList
, Serialized Form
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Constructor Summary
ConstructorDescriptionConstructs a ConcurrentModificationException with no detail message.ConcurrentModificationException(String message)
Constructs aConcurrentModificationException
with the specified detail message.ConcurrentModificationException(String message, Throwable cause)
Constructs a new exception with the specified detail message and cause.Constructs a new exception with the specified cause and a detail message of(cause==null ? null : cause.toString())
(which typically contains the class and detail message ofcause
. -
Method Summary
Methods declared in class java.lang.Throwable
addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString
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Constructor Details
-
ConcurrentModificationException
public ConcurrentModificationException()Constructs a ConcurrentModificationException with no detail message. -
ConcurrentModificationException
Constructs aConcurrentModificationException
with the specified detail message.- Parameters:
message
- the detail message pertaining to this exception.
-
ConcurrentModificationException
Constructs a new exception with the specified cause and a detail message of(cause==null ? null : cause.toString())
(which typically contains the class and detail message ofcause
.- Parameters:
cause
- the cause (which is saved for later retrieval by theThrowable.getCause()
method). (Anull
value is permitted, and indicates that the cause is nonexistent or unknown.)- Since:
- 1.7
-
ConcurrentModificationException
Constructs a new exception with the specified detail message and cause.Note that the detail message associated with
cause
is not automatically incorporated in this exception's detail message.- Parameters:
message
- the detail message (which is saved for later retrieval by theThrowable.getMessage()
method).cause
- the cause (which is saved for later retrieval by theThrowable.getCause()
method). (Anull
value is permitted, and indicates that the cause is nonexistent or unknown.)- Since:
- 1.7
-