How to create an InitialDirContext in an OSGi component inside felix (v603) running on top of jdk15

Question

I am in the process of upgrading my jdk8 code to jdk15 and have most of the dependencies and config settings working but I am struggling with the creation of a new InitialDirContext.

My component is sending out a mail and is setting up the InitialDirContext to get hold of the MX records. The code runs just fine when run as a main, i.e. the creation with property java.naming.factory.initial set to com.sun.jndi.dns.DnsContextFactory works just fine.

public static void main(String[] args) {
    Properties env = new Properties();
    env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");
    try {
        InitialDirContext initialDirContext = new InitialDirContext(env);
        Attributes attrs = initialDirContext.getAttributes("gmail.com", new String[]{"MX"});
        Attribute attr = attrs.get("MX");
        Set<String> hostNames = new HashSet<>();

        if (attr != null) {

            for (int i = 0; i < attr.size(); i++) {
                String mxAttr = (String) attr.get(i);
                String[] parts = mxAttr.split(" ");
                hostNames.add(parts[1].substring(0, parts[1].length() - 1));
                addIpAddresses(initialDirContext, parts[1], hostNames);
            }
        }
        System.out.println("hostNames = " + hostNames.stream().sorted().collect(Collectors.joining(", ")));
    } catch (NamingException e) {
        e.printStackTrace(System.err);
    }
}

However, when I run this type of code inside Felix I am getting the exception:

Caused by: javax.naming.NoInitialContextException: Cannot instantiate class: com.sun.jndi.dns.DnsContextFactory [Root exception is java.lang.IllegalAccessException: class javax.naming.spi.NamingManager (in module java.naming) cannot access class com.sun.jndi.dns.DnsContextFactory (in module jdk.naming.dns) because module jdk.naming.dns does not export com.sun.jndi.dns to module java.naming]
        at java.naming/javax.naming.spi.NamingManager.getFactory(NamingManager.java:749)
        at java.naming/javax.naming.spi.NamingManager.lambda$getInitialContext$1(NamingManager.java:711)
        at java.base/jdk.internal.loader.AbstractClassLoaderValue$Memoizer.get(AbstractClassLoaderValue.java:329)
        at java.base/jdk.internal.loader.AbstractClassLoaderValue.computeIfAbsent(AbstractClassLoaderValue.java:205)
        at java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:711)
        at java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305)
        at java.naming/javax.naming.InitialContext.init(InitialContext.java:236)
        at java.naming/javax.naming.InitialContext.<init>(InitialContext.java:208)
        at java.naming/javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:130)

I can see that the jdk.naming.dns module does not actually export the package com.sun.jndi.dns, but then how is it possible that the code works in a main class? Is there perhaps an additional setting that I need to add to my Felix config.properties file?