When you start working with the Android development tools to develop your first Android Application you will, most likely, be using the Eclipse tools provided and you will most likely start with a HelloWorld example. HelloWorld examples are used in almost every programming guide to show you a "Hello World" text. It is considered the most simple application of showing something on the screen. Google has also provided a Hello World example which will show you how to work with eclipse plugin and how the emulator is working. If you are following the steps in the development guide from Oracle you have to run your application at some point. This is however a point I feel a lot of people will drop it if they are not really determine. The reason is not that it is complex, the reason is that you have to wait and you are not warn that you have to wait.When you run a example the first time you expect it to be on the screen directly. However when you run your HelloWorld example you see the Android Emulator coming up with on the word "ANDROID" in a black screen and not the expected "Hello World" text. Reason for this is quite simple as is the solution. When you click run for the first time the entire emulator has to be started and the "ANDROID" message is the first stage of the boot screen. Solution; wait. After some time you will see the android splash screen coming up and short after that your application. Now you also have a complete Android device and the basic Android OS you can use and play with. Meaning, if you only see "ANDROID" in your screen when you run your application for the first time, do not be afraid, you most likely did not make a mistake you simply have to wait for one or two minutes for the emulator to boot completely. After that you can go back to your development environment and change whatever you like. If you click run the second time and you have closed down your emulator only the new code will be loaded into the emulator and it will not have to be rebooted.