Android by default includes and application called PhoneApp, which actially includes the functions of mobile phone. Intent is an Android API wich actually communicates between different Anrdoid applications to perform certain operations such as initializing a phone call. To enable your application to initialize a phone call the following simple code will serve.
Android apps use SQLite relational database to store information like contacts, events, tasks and application specific data. SQLite database engine is a self-contained transactional database engine that requires no seperate database server process. SQLite is an opensource database actively developed by a large set of community and sponsers like Oracle, Symbian, Mozilla, Adobe, Bloomberg.
Nowadays mobile phones are not just for making calls. It has become a handy computer with which you can be always connected to the world (i.e Internet). As the usage of mobile phones increased drastically so the applications for the mobiles are also increasing with the same pace. Earlier writing mobile applications was difficult and was dependent on phone hardware. With the introduction of J2ME the platform independence has come into picture. Which means that a mobile application can run on all the phones in spite of the vendors (like Nokia, Motorola..). The major lacking in the J2ME is that not able to access the low level (Operating System) feature of the mobile phone. The J2ME has got limited access to the mobiles and hence the applications will also be limited.