Selected 3 fields and tried Refactor > Encapsulate Fields. One of the selected fields was previously encapsulated. IDE
threw java.lang.NullPointerException. Here's the source that caused the problem.

public class ServletController {

    private final UriFromClient uriFromClient;
    private final ClientCommunicator clientCommunicator;
    private final UriParser uriParser;

    public UriFromClient getUriFromClient() {
        return uriFromClient;
    }

    public ServletController(UriFromClient ufm, ClientCommunicator cc, UriParser up) {
        this.uriFromClient = ufm;
        this.clientCommunicator = cc;
        this.uriParser = up;
    }
}