nanohttpd-websocket is a very low profile websocket server based on nanohttpd.
'org.nanohttpd:nanohttpd-websocket:2.3.0'
<dependency>
<groupId>org.nanohttpd</groupId>
<artifactId>nanohttpd-websocket</artifactId>
<version>2.3.0</version>
</dependency>
<dependency org="org.nanohttpd" name="nanohttpd-websocket" rev="2.3.0"/>
"org.nanohttpd", "nanohttpd-websocket", "2.3.0"