A Java EE application or a Java Platform, Enterprise Edition application is any deployable unit of Java EE functionality. This can be a single Java EE module or a group of modules packaged into an EAR file

EAR (file format)

EAR is a file format used by Java EE for packaging one or more modules into a single archive so that the deployment of the various modules onto an application server happens simultaneously and coherently...

 along with a Java EE application deployment descriptor

Deployment Descriptor

A deployment descriptor refers to a configuration file for an artifact that is deployed to some container/engine.In the Java Platform, Enterprise Edition, a deployment descriptor describes how a component, module or application should be deployed...

. Java EE applications are typically engineered to be distributed across multiple computing tiers.

Enterprise applications can consist of the following:

• EJB modules (packaged in JAR files);
• Web modules (packaged in WAR files);
• connector modules or resource adapters (packaged in RAR files);
• Session Initiation Protocol
  Session Initiation Protocol
  The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
  
  (SIP) modules (packaged in SAR files);
• application client modules;
• Additional JAR files containing dependent classes or other components required by the application;
• Any combination of the above.