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{{Mark|Introduced with Version 9.4.}}
If the An XQuery expression will be handled as an [[XQuery Update#Updating Expressions|updating expression]] if it calls an updating Java function is invoked. In contrast to XQuery update operations, it the Java code will immediately be executed (i.e., it will not be postponed as other updating operations), but the result will be cached as if {{Function|Update|update:output}} was called.
{{Mark|Updated with Version 9.4:}} Single annotation for read and write locks.
When If an XQuery expression calls the Java invokes {{Code|write()}} function, every any other query that calls call {{Code|write()}} or {{Code|read()}} needs to wait for the query to be finished. If The {{Code|read()}} is called, function can be run in parallel; only those queries are queued that call {{Code|write()}}.
no edit summary
* The namespace of the function name identifies the Java class.
* The local part of the name, which is rewritten to camel case, identifies a variable or function of that class.
* The middle dot character <code>[httphttps://www.fileformat.info/info/unicode/char/b7/index.htm ·]</code> (&#xB7;, a valid character in XQuery names, but not in Java) can be used to append exact Java parameter types to the function name. Class types must be referenced by their full path.
{| class="wikitable"
Please visit the XQuery 3.0 specification if you want to get more insight into
[httphttps://www.w3.org/TR/xpath-functions-3031/#properties-of-functions function properties].
==Updates==
The {{Code|@Updating}} annotation can be applied to mark Java functions that perform write or update operations:
</syntaxhighlight>
The annotation is particularly helpful if combined with a lock annotation.
==Locking==
By default, a Java function will be executed in parallel with other code. If a Java function performs sensitive operations, it is advisable to explicitly lock the code.
===Java Locks===
Java provides numerous ways a handful of mechanism to synchronize control the execution of code. In simple cases, The concurrent execution of functions can be avoided with the {{Code|synchronized}} keyword can be used. For more complex scenarios, Lock and Semaphor and Atomic classes exist.
===XQuery Locks===
</syntaxhighlight>
More details on parallel query execution concurrent querying can be found in the article on [[Transaction Management]].
==Data Types==
