How to write an applet in java

Examples and practices described in this page don't take advantage of improvements introduced in later releases.

How to write an applet in java

The microprocessor is capable of doing computer-like things such as running programs, processing input and output, and storing data. But unlike most computers, a smart card does not incorporate a display or a keyboard--in fact, it has no power supply.

Because it needs a way to get input and display results, a smart card works in tandem with a card acceptance device CADthat is, a card reader or terminal.

Both of these device types have slots into which a card is placed for reading. Card readers are connected to computers; terminals are themselves computers.

how to write an applet in java

For example, you can use a smart card to "pay-as-you-go. Here you purchase a card that has an initial monetary value. When the current value of the card drops to a low or zero value, you buy another one or go to the appropriate people and have them add more value to the card.

A smart card can also be used to maintain personal records, for example, your medical records. This can be particularly valuable in emergencies, when you might not be physically capable of communicating with medical personnel.

Writing a Java Card Applet

These are just two of an almost limitless number of possible applications for smart cards. Not only can a card be programmed for many different types of applications, but more than one application can be loaded onto a card. If these applications are coded using Java Card technology, the code and data for one application is protected from access and possible damage by the others.

In Java terminology these applications are said to run in their own "sandbox. This is an important convenience to smart card issuers. For example, imagine that a bank has issued smart cards to overof its customers. If the bank needs to update a program on these cards, it simply makes the update available for download on a computer attached to the card reader.

Underlying Concepts

The next time a bank customer swipes the card through the reader, the update is downloaded onto the card; the bank does not have to reissue any smart cards. About Java Card Technology Initially, smart card application development was essentially proprietary.

This usually meant that if company A manufactured smart cards, and company B manufactured smart cards, there was no generic way of coding applications that could run on cards produced by both manufacturers.

As a result, smart card application development was limited to a relatively small group of developers who either worked for the smart card manufacturers or the smart card issuers.

Java Card technology provides an architecture for open application development for smart cards, using the Java programming language. However in recent years, smart card application development has evolved so that it is no longer proprietary.

Now smart card developers can produce applications that can run on cards from different manufacturers. Applications from different developers can run on the same smart card.

This has opened up smart card development to independent application providers. The technology can also be used to develop applications for other devices that have extremely small memory, such as subscriber identity module SIM cards for wireless phones. A SIM card is a smart card with a much smaller plastic substrate than credit-card sized smart cards.

Typically, a SIM card has more memory than other types of smart cards such as bank cards. Java Card technology comprises a set of specifications for the following: An application programming interface API. A virtual machine 1. The virtual machine specification describes the characteristics of the virtual machine for handling Java Card applications.

It consisted of a specification for APIs only. This is an industry consortium that works for the adoption of Java Card technology in the smart card industry. This level of the technology included a JCRE specification. It is available for download. Also available for download is the Java Card 2.

The development kit provides an environment to test Java card applets, and a converter tool that prepares Java Card applets for downloading onto a smart card or onto another device that implements Java Card 2. It also includes sample Java Card applets. You can find the source code file, Wallet.A Java applet is a special kind of Java program that a web browser enabled with Java can download from the internet and run.

A "Hello, World" Applet

An applet is typically embedded inside a . Java Examples Create an Applet: A beginner's tutorial containing complete knowledge of Java Syntax Object Oriented Language, Methods, Overriding, Inheritance.

The "Hello World" Applet By following the steps on this page, you can create and use an applet. If you aren't interested in applets, you might want to skip ahead to the Writing Java Programs trail.

how to write an applet in java

Create a Java . The browser's Java Plug-in software manages the lifecycle of an applet. Use a web server to test the examples in this lesson. The use of local applets is not recommended, and local applets are blocked when the security level setting in the Java Control Panel is set to High or Very High.

import; import*; import*; The first import statement provides a class called Applet, which we'll use in a moment. The other two import statements provide items from the abstract windowing toolkit (the "AWT"), which is a collection of .

"how to write first program of applet.." That is a poor choice of first program. 1) GUIs are inherently more difficult to develop that an app. without a GUI.

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