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 result of a By default, Java call is converted back to XQuery, values with the most common types (as depicted shown in the second and third column of the table) are converted to XQuery values. All other values are returned as ''Java items'', which are function items with a wrapped Java value. The results of constructor calls are always returned as Java items.

As there The conversion of the wrapped Java value to XQuery is enforced by invoking the function item: Values in {{Code|Iterator}} and {{Code|Iterable}} instances (Lists, Sets and Collections) are too many differences between converted to items, and maps are converted to XQuery maps: <syntaxhighlight lang="xquery">declare namespace Scanner = 'java:java.util.Scanner';let $scanner := Scanner:new("A B C") => Scanner:useDelimiter(" ")return $scanner()</syntaxhighlight> If no conversion is defined, a string is returned, resulting from the {{Code|toString()}} method of the object. This method is also called is the string representation of a Java item is requested: <syntaxhighlight lang="xquery">(: returns the string representations of a HashMap and an ArrayList instance :)'Map: ' || Q{java.util.HashMap}new(),string(Q{java:java.util.ArrayList}new())</syntaxhighlight> The conversion can be further controlled with the {{Option|WRAPJAVA}} option. The following values exist: {| class="wikitable"|- valign="top"! Value! Description|- valign="top"| {{Code|some}}| The default: Java values of the most common typesare converted, others are wrapped into Java items.|- valign="top"| {{Code|none}}| All Java values are converted. If no bidirectional mapping conversion is defined, a string is possiblereturned, resulting from the {{Code|toString()}} method.|- valign="top"| {{Code|all}}| Java values are wrapped into Java items (excluding those inheriting the internal type {{Code|org.basex.query.value. The chosen mapping Value}}).|- valign="top"| {{Code|instance}}| If the method of a class instance was called, the Java value is ignored and the instance is wrapped into a compromise between usability Java item. Otherwise, the Java value is returned.|- valign="top"| {{Code|void}}| Java values are ignored, and conformityan empty sequence is returned instead. The |} In the following example, the result of the first function – a char array – is wrapped and passed on to a {{FunctionCode|ConversionCharBuffer}} function. Without the option, the single-value array would be converted to an {{Code|convertxs:unsignedShort}} item and the second function call would fail: <syntaxhighlight lang="xquery">(:from-Without the pragma, the result of toChars would be converted to an xs:unsignedShort item, and the second function call would fail :) (# db:wrapjava all #) { Q{Character}toChars(xs:int(33)) => Q{java.nio.CharBuffer}wrap()} </syntaxhighlight> The next example demonstrates a use case for the {{Code|instance}} option: <syntaxhighlight lang="xquery">(: Thanks to the pragma, the function calls can be used 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-effecting methods return values that do not contribute to convert more complex data structures the final result: <syntaxhighlight lang="xquery">(: Without the pragma, 100 booleans would be returned by the FLWOR expression :) declare namespace set = 'java:java.util.HashSet';let $set := set:new()return ( (# db:wrapjava void #) { for $i in 1 to XQuery100 return set:add($set, $i) }, $set())</syntaxhighlight> The irrelevant results could also be swallowed with {{Function|Profiling|prof:void}}.

* Updated: Java Bindings revised (new mappings, Java functiom items, {{AnchorOption|Data TypesWRAPJAVA}}: {{Code|array(*option)}} type added; {{Code|xs:integer}} are converted to {{Code|long}} values.