Whilst examining the cases in which core reflection internally in the JDK it
was noted that the implementation class of java.awt.print.PrinterJob is
located via a System property java.awt.printerjob.

This lead to a question as to whether this is a "pluggable" SPI that
can be over-ridden by external code. There was in fact no such intention
and it was just a convenience. See the docs in System.c which say :

  /* Note: java.awt.printerjob is an implementation private property which
     * just happens to have a java.* name because it is referenced in
     * a java.awt class. It is the mechanism by which the implementation
     * finds the appropriate class in the JRE for the platform.
     * It is explicitly not designed to be overridden by clients as
     * a way of replacing the implementation class, and in any case
     * the mechanism by which the class is loaded is constrained to only
     * find and load classes that are part of the JRE.
     * This property may be removed if that mechanism is redesigned
     */
    PUTPROP(props, "java.awt.printerjob", sprops->printerJob);

It may be best to do that and stop this internal property from polluting the public properties.