RMI technology and its application in mobile communication

1. introduction

Java Smart Card (Java Card) technology is extremely widely used in the third generation of mobile communication (3G1. The emergence of Jaya smart card. It allows multiple applications to coexist in a smart card. These applications can come from the same card supplier. It can also come from different card suppliers. Users only need to refresh the program on the smart card. They can get different applications. Operators and developers get rid of the dependence on card vendors. The cost is greatly reduced. In the SIM card of mobile communication The application of Java smart cards is more and more extensive, and the prospect is extremely optimistic. Because the amount of Java smart cards used by SIM cards is increasing, the frequency of use is getting higher and higher. In order to better play the processing of the network and the computers distributed in the network Capability. The RMI technology of Java smart card in mobile communication becomes more and more important in the development and application.

2. The main characteristics of Java smart card in mobile communication

In mobile communications, a Java smart card refers to a smart card that runs a Java applet. The corresponding Java virtual machine must be present on the card. The applet that conforms to the Java Card technical specification can run on the virtual machine. SUN has proposed the Java Card technical specification. Includes detailed information about creating a Java Card virtual machine on a smart card and application programming interface 1: 3 (API). Compared with the traditional smart card system, the Java smart card platform has the following characteristics:

1. Cross-platform

At present, most SIM cards in mobile communication already support the technical specifications of Java cards. Any Java Card Applets that conform to the Java Card API technical specifications can be run in the Java Card Run Environment (JCRE: Java Card RunTIme Environment). Developers are allowed to use the same Java card Applets to run on smart cards of different manufacturers, and realize the function of one-time program writing to run everywhere, that is, to achieve the purpose of cross-platform through the JVM mechanism.

2. Application development convenience

For applications on Java smart cards in mobile communications, developers can develop smart card applications without understanding the complex smart card hardware and smart card-specific technologies, thereby greatly reducing development time, reducing development difficulty and cost. And can make the original Java program developers to write smart card programs. Human resources are fully utilized to better meet the needs of exponential growth of applications. At the same time, it is also necessary for the development of the times.

3. safety

In mobile communications, Java smart cards are one of the most critical issues. Security involves multiple aspects. The security mode of the Java smart card system has been improved in many aspects. Its security strategy is implemented by the Java Card Virtual Machine (fJCVM) and the Java Card Runtime Environment. Considering the application scope of the smart card and the particularity of the application, the Java card supports the protection of data integrity and prevents unauthorized access to sensitive data.

4. Multi-application

In a Jaya card operating environment, you can run a variety of different applications (Applets) with very different functions, such as mobile Internet access, mobile securities trading, mobile phone games, etc. These applications can come from the same card supplier or from different card suppliers, which is a very important feature of the new generation of mobile phones.

3. RMI technology and RMI technology of smart card in mobile communication and its application

3.1 RMI technology

RMI (Remote Method InvocaTIon) technology in J2SE is the core technology for developing Java distributed network applications. Unlike traditional RPC (Remote Procedure Call, remote procedure call) calling remote procedures, RMI is used to call remote objects. method. Support communication between objects stored in different address spaces. Let objects located in different JVM spaces be used like local objects in appearance and behavior. It is the core solution of developing network distributed application system in pure object-oriented Java program.

The application program developed by RMI is composed of two parts: server program and client program. The server-side program will create multiple object instances at runtime (called remote objects). These object instances are used to provide certain services to customers. At the same time, the server opens the listening port and waits for the client program to call. The client program obtains the reference of the remote object from the server through the RMI mechanism at runtime. Call the party

The architecture of RMI can be represented by Figure 1:

As can be seen from Figure 1, the RMI architecture is composed of multiple layers. The stub / skeleton layer uses the stub framework (ske1eton) method to hide the implementation details of the underlying communication. The stub represents the client object of the remote object. Has the same interface or method list as the remote object. When the client program calls the method of the remote object. In fact, the method in the stub object is called. The stub forwards the request to the remote object. The skeleton object on the server side is responsible for decoding the information from the stub. The decoded information is handed over to the actual remote object for processing. After the remote object is processed, the result is passed to the skeleton object. Then the skeleton object is passed to the client's stub object, and finally the stub object passes this information to the client program.

China Glass Diffuser ,Glass Essential Oil Diffuser,Aromatherapy Essential Oil Diffuser Manufacturer

  • Special Glass Cover Design: This glass diffuser is use Glass cover and PP water tank. It gives us a lovely aromatherapy, make us relax and enjoy our whole day.
  • Super Quiet Operation: Using ultrasonic technology, this Aromatherapy Oil Diffuser produce smooth and continuous mist to humidify the air and fragrance home. Whisper-quiet operation won't affect quality of sleep.
  • Waterless Shut-off: The Aromatherapy Essential Oil Diffuser with high capacity, gives a smooth mist and nice fragrance to bedroom, and will shut-off auto when the water runs out.
  • Gorgeous 7 Colors Light: This Aromatherapy Essential Oil Diffuser has 7 changing color lights, each colors can be changed or fixed, creating a calm and soft atmosphere when you are working, reading, studying or sleeping.

Glass Diffuser

Glass Diffuser,Glass Essential Oil Diffuser,Aromatherapy Essential Oil Diffuser,Aromatherapy Oil Diffuser

Shenzhen Dituo Electronic Co.,Ltd. , https://www.sz-dituo.com