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Certain thread APIs were introduced to facilitate thread suspension, resumption, and termination but were later deprecated because of inherent design weaknesses. For example, the Thread.stop() method causes the thread to immediately throw a ThreadDeath exception, which usually stops the thread. More information about deprecated methods is available in rule MET02-J. Do not use deprecated or obsolete classes or methods.

Wiki MarkupInvoking {{Thread.stop()}} results in the release of all locks a thread has acquired, potentially exposing the objects protected by those locks when those objects are in an inconsistent state. The thread might catch the {{ThreadDeath}} exception and use a {{finally}} block in an attempt to repair the inconsistent object or objects. However, this requires careful inspection of all synchronized methods and blocks because a {{ThreadDeath}} exception can be thrown at any point during the thread's execution. Furthermore, code must be protected from {{ThreadDeath}} exceptions that might occur while executing {{catch}} or {{finally}} blocks \ [[Sun 1999|AA. References#Sun 99]\]. Consequently, programs must not invoke {{Thread.stop()}}.

Removing the java.lang.RuntimePermission stopThread permission from the security policy file prevents threads from being stopped using the Thread.stop() method. Although this approach guarantees that the program cannot use the Thread.stop() method, it is nevertheless strongly discouraged. Existing trusted, custom-developed code that uses the Thread.stop() method presumably depends on the ability of the system to perform this action. Furthermore, the system might fail to correctly handle the resulting security exception. Additionally, third-party libraries may also depend on use of the Thread.stop() method.

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Because the Vector class is thread-safe, operations performed by multiple threads on its shared instance are expected to leave it in a consistent state. For instance, the Vector.size() method always returns the correct number of elements in the vector, even after concurrent changes to the vector, because the vector instance uses its own intrinsic lock to prevent other threads from accessing it while its state is temporarily inconsistent.

Wiki MarkupHowever, the {{Thread.stop()}} method causes the thread to stop what it is doing and throw a {{ThreadDeath}} exception. All acquired locks are subsequently released \[ [API 2006|AA. References#API 06]\]. If the thread were in the process of adding a new integer to the vector when it was stopped, the vector would become accessible while it is in an inconsistent state. For example, this could result in {{Vector.size()}} returning an incorrect element count because the element count is incremented after adding the element.

Compliant Solution (volatile flag)

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Bibliography

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[[API 2006AA. References#API 06]]	Class Thread, method stop, interface ExecutorService
]]></ac:plain-text-body></ac:structured-macro>	<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="30cd2dcf-8212-43fa-b6f4-c09e2d7f4b3e"><ac:plain-text-body><! [CDATA[ [[Sun 1999AA. References#Sun 99]]		]]></ac:plain-text-body></ac:structured-macro>	<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="a9f9eb7a-96ee-42eb-b251-0739c23a33e3"><ac:plain-text-body><![CDATA[
[[Darwin 2004AA. References#Darwin 04]]	24.3, Stopping a Thread	]]></ac:plain-text-body></ac:structured-macro>	<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="3a853969-9d14-4d38-bf42-88b066c9353a"><ac:plain-text-body><![CDATA[
[ [JDK7 2008AA. References#JDK7 08]]	Concurrency Utilities, More information: Java Thread Primitive Deprecation	]]></ac:plain-text-body></ac:structured-macro>	<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="8d0cd136-b12b-4673-9347-a79b30377ea2"><ac:plain-text-body><![CDATA[
[[JPL 2006AA. References#JPL 06] ]	14.12.1, Don't Stop; 23.3.3, Shutdown Strategies	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="5f151e2a-d7af-48d2-a29f-28e918c703bc"><ac:plain-text-body><![CDATA[	[ [JavaThreads 2004AA. References#JavaThreads 04] ]	2.4, Two Approaches to Stopping a Thread ]]></ac:plain-text-body></ac:structured-macro>	<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="7f5a0ffa-46ae-4a34-b35c-6928481aad6a"><ac:plain-text-body><![CDATA[
[ [Goetz 2006AA. References#Goetz 06] ]	Chapter 7, Cancellation and Shutdown ]]></ac:plain-text-body></ac:structured-macro>

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      09. Thread APIs (THI)      10. Thread Pools (TPS)