1. A method, comprising: deploying, by a Session Initiation Protocol (SIP) Servlets application server executed by a processing device, a JRuby™ application to provide Voice over Internet Protocol (VoIP) services, wherein the SIP Servlets application server is integrated with a JAVA Enterprise Edition™ (JAVA EE) application server as a single integrated stack running in a single JAVA virtual machine (JVM); and associating, by the SIP Servlets application server, the JRuby™ application deployed in the SIP Servlets application server with the JAVA EE application server, the associating comprising updating a deployment file in a Ruby™ adaptation layer of the JAVA EE application server with a name of the JRuby™ application in a SIP configuration section of the deployment file and a name of a class that handles SIP messages.