Java Bindings

The Java Binding feature is an extensibility mechanism which allows direct calling of Java methods bound as XQuery functions and manipulation of wrapped Java objects. The following examples introduce the behavior. Please note that the namespace URI must be of the form java:fullyQualifiedClassName.

This example uses the java Math class and returns the cosine of an angle:

declare namespace math = "java:java.lang.Math";
math:cos(xs:double(0))

Note: To call a method directly it has to be set as static in you java code.

The next example writes 256 bytes to the file output.txt. To call the write method of the FileWriter class, you have to pass a class instance as first argument:

declare namespace fw = "java:java.io.FileWriter";
 
let $file := fw:new('output.txt')
return (
  for $i in 0 to 255
  return fw:write($file, xs:int($i)),
  fw:close($file)
 )

Note that we recommend to use XQuery specific functions and expressions whenever possible, as Java code cannot be pre-compiled by BaseX, and will mostly be evaluated slower than pure XQuery code.