Chapter 10: Software Development Security - Mobile Code

Mobile code is code that can be send to another location across a network and then be executed and used on the other side. In Java, Java applets are used to accomplish this. The programmer creates the applet, runs the program through a compiler and is turned into bytecode (this code is not platform specific; it can run on many platforms. This bytecode is then placed on a server available for users to download it. Once a user downloads it, the universal bytecode is then transformed into machine-level code that is specific to the type of system it was downloaded to. To accomplish this code conversion, a Java Virtual Machine is used. Usually this virtual machine is running within the users web browser. The applet is then able to be ran when it is called upson, but it is ran in what is known as a sandbox. A sandbox is an area in where potentially unsafe code from another area can be ran in a secure manner.