This lets me do something like this:

JsonSchemaFactory factory = JsonSchemaFactory.builder(JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V7))
            .uriFetcher(new JenkinsWorkspaceFileFetcher(), JenkinsWorkspaceFileFetcher.SUPPORTED_SCHEMES)

JenkinsWorkspaceFileFetcher.SUPPORTED_SCHEMES is a Set<String>, which can't be passed into varargs. But varargs can be passed into an Iterable<String> if you wrap it with Arrays.asList(varargs), and it is cheap too since an ArrayList<> is just backed by an array.