The goal of this thesis is to gain some know-how in the area of programming MIDlets. Those are applications that are designed to run on wireless Java enabled devices such as cellphones. The first development platform for MIDlets, covering a wide range of manufacturers, was developed by Java with the Java 2 Micro Edition(J2ME). The possibilities of MIDlets are pointed out in the four example applications.

As a first off-line application, an IQ-Test was developed. This provides an insight into programming MIDlets and was used to become familiar with MIDlets.

The second off-line application, a diary for a diabetic, was programmed on request. Using it, the diabetic is able to store his injection data daily on the cellphone. They are valid for a month. The Siemens function package was used for this purpose because it permits a persistent storing of data on the Multi Media Card(MMC) of the Siemens SL45i mobile telephone. Based on the IQ test, text-, date- and time fields were added as well as calendar functions.

Chat was implemented as the third application. Owing to GPRS technology, it allows an economical communication between two mobile telephones. Since this communication is only possible by means of a server via internet, a Apache Tomcat Web server was set up. On this server a Java Servlet, a Java application that can be started by a HTTP-Request, was installed. This receives the data sent from the MIDlet, processes it and sends the current chattext back as an answer. Since a Servlet can receive inquiries of several MIDlets, the communication problem is solved.

The fourth and last application makes it possible to inquire about the current Swiss daily weather forecast by MIDlet. Two MIDlets were programmed whereby the first loads the weather forecast directly from the server. The other one reads the weather forecast indirectly over a Servlet.