https://git.opendaylight.org/gerrit/#/c/68840/ pointed to 
yangtools.util.ClassLoaderUtils's{{withClassLoader(...)}}, but this method is hard to use in practice with Java 8 lambdas (perhaps it was written before Java 8) because it has overloaded Supplier as well as Callable signatures, therefore e.g. something like this:

ClassLoaderUtils.withClassLoader(KarafIniWebEnvironment.class.getClassLoader(), () -> {
 return factory.getInstance();
});

 
fails with:

The method withClassLoader(ClassLoader, Supplier<SecurityManager>) is ambiguous for the type ClassLoaderUtils

this can be worked around with a cast like this of course, but this is cumbersome:

ClassLoaderUtils.withClassLoader(
                KarafIniWebEnvironment.class.getClassLoader(), (Supplier<SecurityManager>) factory::getInstance);