Preferences store preference data on disk in files named using an application ID that you provide. To ensure that there are no naming conflicts, it’s a good idea to define and set a bundle identifier for your application and use it as the application ID for preferences. Bundle identifiers take the same form as Java package names—your company’s unique domain name followed by the application or library name—for example
com.foo.ImageImport. Using this scheme minimizes the possibility of collision, and leaves you responsible for managing the identifier namespace under your corporate domain. See Bundle Programming Guide for more information on bundles and bundle IDs.