JAR file format is based on the popular ZIP file format. Different from ZIP files, JAR files are not only used for compression and publishing, but also for deploying and encapsulating libraries, components and plug-ins, which can be directly used by compilers, JVMs and other tools. JAR contains some special files, such as manifest and deployment descriptor, which are used to instruct tools how to deal with a specific JAR.
JAR files can be used to:
□ Used for publishing and using class libraries.
□ As a building block for applications and extensions
□ As a deployment unit of a component, applet or plug-in.
□ Used for packaging auxiliary resources related to components.
Sis is a silicon system technology, and the so-called sis software refers to the installation package software specially developed for smartphones with Symbian operating system 60 series platform (s 60) and above.
Nokia's symbian system for smart phones has undergone three major system upgrades since 7650, namely os6, os7/8 and os9. 1. The software formats of the first and second editions of the system, namely os6, OS7 and OS8, are all sis. Although some of them are incompatible with each other, most of them can still be used universally, and it is convenient to modify them when they are incompatible. However, in the third edition, os9. 1 uses a new security kernel and compiler, which is completely incompatible with the first and second editions. It is very troublesome to modify and needs to rewrite the program. Therefore, in order to be different from the previous edition, the third editions such as 3250 use sisx as the new format.