Introducing Java driver 4

Java driver 4.0.0-alpha1 has been released, marking the first preview of the next major version. This release includes breaking API changes to address longstanding issues and is available from Maven central with updated coordinates. The sources are on GitHub's 4.x branch. Though functional, this alpha release lacks many features and is not production-ready. A feature-complete beta is expected in the upcoming months. Feedback can be provided via the mailing list or by contributing to open tickets.