6.5 Why is Android using Java without C implementation?

　　C + + is too low level, developers have to spend a lot of experience on C + + language research Clearly, such as the memory mechanism, if a little attention, will forget to open or release. and Java's GC automatically handles this, saving a lot of time for developers to focus on their business. As a result, the Java development language is slowly moving up from the bottom of C + +, which interacts through the JNI and core runtime layers. In fact, these are the reasons why Java can develop so quickly, the advantage of the language of the phenomenon object. It takes time to create new things without being too concerned about memory. Example:

• Activity Manager: Used to manage the application life cycle and provide common navigation fallback functionality.
• Window Manager: Provides some ways to access your phone's screen. The transparency, brightness, and background of the screen.
• Content Providers: Enables applications to access data from other applications, such as contact databases, or to share their own data.
• View System: Can be used to build applications, which include lists, grids, text boxes, buttons, and even embeddable web browsers.
• Notification Manager: Enables applications to display customized prompts in the status bar.
• Package Manager: Provides access to the system's installation packages. This includes installing, uninstalling apps, querying permissions and application related information, and more.
• Telephony Manager: Mainly provides a way to access the status and information related to mobile phone communication, query the status of telecommunications networks, SIM card information and so on.
• Resource Manager: Provides access to non-code resources, such as local strings, graphics, and layout files.
• Location Manager: Provides a way to get the address of the device. Obviously, GPS navigation is sure to be able to use location services.

6.5 Why is Android using Java without C implementation?