Sometimes one wants to register a custom extension function net.sf.saxon.lib.ExtensionFunctionDefinition in the saxon xquery engine context.
When providing XQueryBuilder.setConfiguration(Configuration configuration) with such configuration, the method will set the context and also set the initialise flag to false (line 378). This will cause XQueryBuilder.initialize(Exchange exchange) to run next time the builder is used.
Unfortunately the initialize method on line 639 it will create a new saxon Configuration regardless of what was set in the XQueryBuilder.setConfiguration() and renders this function pretty much useless.
The obvious solution to this problem is to check if the configuration is null before creating a new saxon configuration.