Access to memory
The BlackBerry Java environment is designed to prevent apps from causing problems accidentally or maliciously in other apps or on the BlackBerry smartphone. Apps can write only to the smartphone memory that the BlackBerry Java Virtual Machine uses; they cannot access the virtual memory or the persistent storage of other apps (unless they are specifically granted access to do so). Your apps can only access persistent storage or user data, or communicate with other apps, through specific APIs. Research In Motion must digitally sign apps that use certain BlackBerry APIs to provide an audit trail of apps that use sensitive APIs.