Changes

The normalization steps are skipped if the URI is prefixed with {{Code|java:}}. The path to the standard package {{Code|java.lang.}} can be omitted:

Java constructors, functions and variables can be referenced and evaluated by the existing XQuery function syntax:

* The middle dot character <code>[https://www.fileformat.info/info/unicode/char/b7/index.htm ·]</code> (<code>&amp;#xB7;</code>, 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. Three adjacent dots can be used to address an array argument.

! TypeAddressed code

| <code>Q{java.lang.Integer}MIN_VALUE()</code>| <code>[https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html#MAX_VALUE Integer.MIN_VALUE]</code>

| <code>Q{java.lang.Object}hash-code($object)</code>| <code>[https://docsobject.oracle.comhashCode()</javase/8/docs/api/java/lang/Object.html#hashCodecode>|- valign="top"| Function with argument| <code>Q{String}split·String·int($string, ';', xs:int(3)) object</code>| <code>string.hashCodesplit(";", 3)]</code>

| Function Constructor with typesarray argument| <code>Q{java.lang.String}split·javanew·byte..lang.String·int($string, ';', xs:inthexBinary(3'414243'))</code>| <code>[https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#split-java.lang.new String-int- string.split(";"new byte[] { 41, 42, 343 })]</code>

As XQuery and Java have different type systems, XQuery arguments are must be converted to equivalent Java values, and the result of a Java function is converted back to an XQuery value (see [[#Data Types|Data Types]]).

In the following example, Java’s the Java {{Code|Math}} class is referenced. When executed, the query returns the cosine of an angle by calling the static method {{Code|cos()}}, and the value of π by addressing the static variable via {{Code|PI()}}:

With the [[XQuery 3.0#Expanded QNames|Expanded QName]] notation of XQuery 3.0,the namespace can directly be embedded in the function call:

declare namespace fw = "'java:java.io.FileWriter"';

declare namespace br = 'java:java.io.BufferedReader';declare namespace fr = 'java:java.io.FileReader';

(: read file :)let $br := br:new(fr:new('00.bin'))return ( br:readLine($br), br:close($br))</syntaxhighlight> The option can also be specified via a pragma: <syntaxhighlight lang="xquery">(# db:checkstrings #) { br:new(fr:new('00.bin')) ! (br:readLine(.), br:close(.))}

The conversion back By default, Java values with the most common types (as shown in the second and third column of the table) are converted to XQuery can be controlled values. All other values are returned as ''Java items'', which are function items with the {{Option|WRAPJAVA}} optiona wrapped Java value. The following values exist:results of constructor calls are always returned as Java items.

* {{Code|some}} (The conversion of the default): wrapped Java values with the most common types are converted value to XQuery, as shown in the second and third column of the table.* {{Code|none}}: The conversion is enforcedby invoking the function item: Additional to the default conversions, values of type Values in {{Code|Iterator}} and {{Code|Iterable}} instances (including Lists, Sets and Collections) are converted to sequencesitems, and maps are converted to XQuery maps. If no conversion is possible, an error is raised. With {{Function|Conversion|convert:from- <syntaxhighlight lang="xquery">declare namespace Scanner = 'java:java}}, the conversion of a wrapped Java object can be enforced.util.Scanner';* {{Code|all}}let $scanner := Scanner:new("A B C") => Scanner: All values useDelimiter(" ")return $scanner(excluding those inheriting the internal type {{Code|org.basex.query.value.Value}}) are returned as wrapped Java objects. The wrapped objects can be passed on to other Java functions without intermediate conversions.</syntaxhighlight>

The option can be specified via If no conversion is defined, a pragma. In the following examplestring is returned, resulting from the result of the first function – a char array – is wrapped and passed on to a {{Code|CharBuffertoString()}} functionmethod of the object. This method is also called is the string representation of a Java item is requested:

Q{java.lang.Character}toChars(xs:int(33))

Without The next example demonstrates a use case for the {{Code|instance}} option: <syntaxhighlight lang="xquery">(: Thanks to the pragma, the singlefunction calls can be chained :) declare namespace set = 'java:java.util.HashSet';let $set := (# db:wrapjava instance #) { set:new() => set:add('1') => set:add('2')}return $set()</syntaxhighlight> The {{Code|void}} option is helpful if side-value array effecting methods return values that do not contribute to the final result: <syntaxhighlight lang="xquery">(: Without the pragma, 100 booleans would be converted returned by the FLWOR expression :) declare namespace set = 'java:java.util.HashSet';let $set := set:new()return ( (# db:wrapjava void #) { for $i in 1 to an 100 return set:add($set, $i) }, $set())</syntaxhighlight> The irrelevant results could also be swallowed with {{CodeFunction|Profiling|xsprof:unsignedShortvoid}} item and the second function call would fail.