Daemon threads for WebSocket keepalives

Sat, 29 Aug 2026 00:00:00 +0000

A WebSocket connection that needs periodic pings to stay open shouldn’t run that ping loop on a plain, non-daemon thread. In the WazirX Java connector , the ping thread is started onOpen and marked setDaemon(true) before starting it:

pingThread = new Thread(new PingMessage(this));
pingThread.setDaemon(true);
pingThread.start();

A non-daemon thread keeps the JVM alive until it finishes. If a caller opens a socket, forgets to close it, and the rest of the application shuts down, a non-daemon ping thread will keep the process running indefinitely. A daemon thread just gets killed when everything else is done — which is the right default for background keepalive work that isn’t itself the point of the program.

WazirX Java Connector

Sun, 23 Aug 2026 00:00:00 +0000

After building the Go connector for WazirX, I wanted the same thing on the JVM — but WazirX doesn’t publish an official Java client at all, REST or WebSocket. The REST half was a fairly direct port of what I’d already learned building the Go client. The WebSocket half turned out to be its own project.

Letting callers choose their failure granularity

For errors, I didn’t want every caller forced into one giant catch-all exception, but I also didn’t want to force a try/catch at every single call site. I split errors into two, with one extending the other:

WebSocket on Prateek Sharma

Daemon threads for WebSocket keepalives

WazirX Java Connector

Letting callers choose their failure granularity