Question

For the “Hello World” example in android.com, the package name is
"package com.example.helloandroid;"

Is there any guideline/standard to name this package? (references would be nice)

Answer 1

Android follows normal java package conventions plus here is an important snippet of text to read (this is important regarding the wide use of xml files while developing on android).

The reason for having it in reverse order is to do with the layout on the storage media. If you consider each period (‘.’) in the application name as a path separator, all applications from a publisher would sit together in the path hierarchy.
So, for instance, packages from Adobe would be of the form:

com.adobe.reader (Adobe Reader)

com.adobe.photoshop (Adobe Photoshop)

com.adobe.ideas (Adobe Ideas)

[Note that this is just an illustration and these may not be the exact package names.]

These could internally be mapped (respectively) to:

com/adobe/reader

com/adobe/photoshop

com/adobe/ideas

The concept comes from Package Naming Conventions in Java, more about which can be read
here:*

http://en.wikipedia.org/wiki/Java_package#Package_naming_conventions

Source: http://www.quora.com/Why-do-a-majority-of-Android-package-names-begin-with-com