| Service is like an Activity but has no interface. | A Thread is a concurrent unit of execution. |
| A Service is not a separate process. It works in background until the service or someone else explicitly stop it. | By default, all components of the same application run in the same process and thread (called the “main” thread). |
| Service is not killed when an application is killed. | Thread is killed when an Application is killed. |
| It expose some of its functionality to other applications by calling Context.bindService(). | GOOGLE has brought in Handlers and loopers into android threads. |