Slack has a Java server managing real-time messaging: https://www.quora.com/What-is-the-tech-stack-behind-Slack https://www.quora.com/What-is-the-tech-stack-beh

Slack has a Java server managing real-time messaging: https://www.quora.com/What-is-the-tech-stack-behind-Slack https://www.quora.com/What-is-the-tech-stack-behind-Slack “This part of our back-end, responsible for most of the real-time interactions happening in various clients, is implemented in Java, and accessed via a WebSocket API described here: Real Time Messaging API. A great deal of the user experience that makes Slack feel like Slack is the result of careful work on the message server. Many of the distributed systems challenges we face on the back-end are in coordinating this service with the rest of the (LAMP-ier) back-end.”