It's required to restart server because added jar is not added to classpath of Remote JVM.
Either restart server or kill Remote JVM by identifying the PID using jmx-console.
Steps:
1) Open http://<host>:<port>/jmx-console
2) Click on Spatial:name=Process,type=Remote Component
3) Attribute "RuntimeName" value has <PID>@<HOST>
4) Kill the Remote JVM process using PID
5) Send Request