Github user franz1981 commented on the issue:
And it makes sense, but there are parts like:
`String name = usersByDn.get(dn);`
that are not synchronized, hence it won't be thread-safe.
My advice is to use a lazy initialization using a `Suppliers::memoize` or
similar construct and always use `Supplier::get` to access the variable: that
would allow to have always a thread-safe access to an unmodifiable resource,