Rahul Chavan have you seen this page? https://doc.nuxeo.com/nxdoc/howto-contribute-to-the-rest-api/ it points to the documentation. I have done a few REST APIs for Nuxeo. I must be in a different module than the Operations and it must be on the package {{package org.nuxeo.ecm.restapi.server.jaxrs;}} and METAINF must be properly configured. Hotreload doesn't work proper with custom REST API and remote debugging can be a bit flick