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Modifying a Collection while iterating over it results in undefined behavior.

Rule	Severity	Likelihood

Remediation Cost

Detectable	Repairable	Priority	Level
MSC06-J	Low	Probable	No

Medium

No

P4

P2

L3

Some static analysis tools can detect cases where an iterator is being used after the source container of the iterator is modified.

Tool	Version	Checker	Description
Parasoft Jtest

9.5BD.CO.ITMODImplemented

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	Parasoft_V
	Parasoft_V

CERT.MSC06.ITMOD

Do not modify collection while iterating over it

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	PVS-Studio_V
	PVS-Studio_V

V6053

Related Vulnerabilities

The Apache Harmony bug HARMONY-6236 documents an ArrayList breaking when given concurrent collections as input.

[API 2014]	Class `ConcurrentModificationException` Interface `Iterator<E>`
[Goetz 2006a]	Section 5.1.2, "Iterators and `ConcurrentModificationException`"
[SDN 2008]	Sun Bug database, Bug ID 6687277

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