JNDI was updated via JDK-8044627 to locate JNDI providers that implement InitialContextFactory using ServiceLoader.

A second phase is required to support JNDI URLs, in particular methods such as javax.naming.spi.NamingManager.getURLContext that map the URL scheme to the class name of an object factory. This mechanism (and spec) should be re-examined to use ServiceLoader to locate implementations of a service type. The service type might define the getScheme method to indicate the URL scheme that it supports.

As part of this effort then Context.URL_PKG_PREFIXES should be examined, maybe it is time to deprecate this mechanism for locating URL context factories.