API control and code signing
When you develop a BlackBerry® Java Application for BlackBerry devices, you can use only the public Java APIs that are published and documented in the Javadoc™ documents in the BlackBerry® Java® Development Environment. The BlackBerry® Java® Virtual Machine on the BlackBerry device is designed to protect the underlying data and operating system, so applications cannot call undocumented or unsupported APIs or access data that is not explicitly exposed through the APIs. If you try to use Java APIs that are not publicly exposed, your application receives an error message at runtime.
Public APIs are either open or signed. Signed APIs expose the methods to access BlackBerry device user data or other information on the BlackBerry device that is considered sensitive. You can use signed APIs, but you must request and receive a set of code signing keys from Research In Motion. You must then digitally sign your application before you install it on a BlackBerry device. Code signing does not certify or approve an application; it allowsRIM to identify the author of an application that uses sensitive APIs, if the application is malicious.
To request a set of code signing keys, visit www.blackberry.com/developers/downloads/jde/api.shtml. You will receive your set of code signing keys in about 10 days.