Guided by Bipin Ajay , It is a very helpful article for IT aspirants.
The tools those are essential /available for Java programming environment are JDK(Java Developer�s Kit), Java Packages, Java Enabled web browsers and other Third party tools. Each of these are briefly outlined below :
Java Developer�s Kit (JDK)
The Java Developer�s Kit from Java Soft, a division of Sun Micro systems, contains the basic tools and libraries necessary for creating and executing Java programs. It consist of a library of standard classes and a collection of utilities for building, testing, and documenting Java programs. The core Java Application Programming Interface (API) is the aforementioned library of prefabricated classes. One need these classes to access the core functionality of the Java language. The core Java API includes some important language construct (including string data types and exceptions ), as well as basic graphics, network, and file I/O. As for the JDK utilities, there are seven main programs in the kit :
1.javac:The Java compiler. This program compiles Java source codes into byte codes.
2.java:The Java interpreter. This program runs Java byte codes.
3.javadoc:Generates API documentation in HTML format from Java source code.
4.appletviewer:A Java interpreter that executes Java applet (a special kind of Java Program) classes.
5.jdb:The Java debugger. Helps us find and fix bugs in Java programs.
6.javap:The Java disassembler. Displays the accessible functions and data in a compiled class file. It also displays the meaning of the byte codes.
7.javah:Creates C header files that can be used to make C routines, that can call Java routines,or make C routines that can be called by Java programs.
JDK is a free software and can be down loaded from Java Soft�s web site at http://java .sun.com
Java Packages
The Java language provides suite of packages that include a windowing tool kit, utilities,, general I/O, tools, and networking. Following mentioned six packages are very popular:
1.java.applet: This package includes classes designed for use within an applet. There is one class, Applet and three interfaces AppletContex, AppletStub, and AudioClip.
2.java.awt :The Abstract Windowing Toolkit (AWT) package, awt, contains classes used to generate widgets and GUI (Graphical User Interface) components. This package includes the classes: Button, CheckBox, Choice, Component, Graphics, Menu, Panel, TextArea, and TextField.
3.java.io :The I/O Package include file input and output classes such as the classes FileInputStream and FileOutputStream. File I/O in subject to Security Control in applets.
4.java.lang:This package includes the Java language classes, including Object, Thread, Exception, System, Integer, Float, Math, String, and so on.
5.java.net :This class supports the TCP/IP networking protocols and includes the Socket, SenverSocket, DatagramPacket, DategramSocket, URL, and URLConnection classes among others.
6.java.util:This class packages contains miscellaneons classes that are useful for a variety of programming chores. Those classes include Date, Dictionary, Random (for creating random number), Vector, and Stack (for implementing a last-in-first-out (LIFO) stack).
Java -Enabled Web Browser
With Internet, Web Browser is a very important program. A Web Browser is nothing but a viewer program used by the client machine to display Web documents. A Jab-Enabled browser is a browser that supports Java applets. Currently many Java-capable Web Browser are known, out of which, most popular are HotJava, Netscape Navigator, and Microsoft Internet Explorer. All these Browser software are free releases and can be down loaded from the respective manufacturer�s web site as listed below:
1.HotiJova from Java soft�s Web sitehttp://java.sun.com
2.Navigator from Netscape�s home pagehttp://home.netscape.com
3.Internet Explorer from Microsoft�s Web page http://www.microsoft.com
Other Third-party Tools
A lot of third party tools are currently available in the market in order to support the productivity of the software development using Java. Important of them are listed as below:
1.Sun�s Java Workshop dev 5 from Sun�s Javasoft provids most robust development environment for Java. The recent addition with this is Visual Java.
2.Ed for Windows from Soft As It Get provides an Integrated Development Environment ( IDE) for Java. It makes Java programming extremely easy and also provides one of the most powefull source code editor.
3.Mojo from Penumbra Software is one of the best visual environments for creating Java applets. Its primary goal is to allow rapid generation of Java applets without writing code.
4.Jamba from Aimtech and IBM is another graphical applet builder and very powerful in Java environment.
5.Semantic Cafe from Semantic another very powerful and is fully integrated Development Environment (IDE). This is aimed for professional application developers and programmers. Currently Cafe is the de facto standard for Java development on Windows NT/95.
Assignment
Q:Explain JDK, JRE and JVM.Q:Why Java is platform independent?Q:Why java is not 100% Object-oriented?Q:List any five features of Java?Q:Which component is used to compile, debug and execute java program?Q:Which component is responsible to run java program?Q:What is use of interpreter?
Q&A
Q:I know a lot about HTML, but not much about computer programming. Can I still write Java programs?A:If you have no programming experience whatsoever, you most likely will find programming Java significantly more difficult than HTML. However, Java is an excellent language to learn programming with, and if you patiently work through the examples and the exercises in this book, you should be able to learn enough to get started with Java.Q:What’s the relationship between JavaScript and Java?A:They have the same first four letters.
A common misconception in the Web world today is that Java and JavaScript have more in common than they actually do. Java is the general-purpose programming language that you’ll learn about in this book; you use it to create applets. JavaScript is a Netscape-invented scripting language that looks sort of like Java; with it you can do various nifty things in Web pages. They are independent languages, used for different purposes. If you’re interested in JavaScript programming, you’ll want to pick up another book, such as Teach Yourself JavaScript in a Week or Laura Lemay’s Web Workshop: JavaScript, both also available from Sams.net Publishing.Q:What is Hot Java?A:Hot Java was the first Web browser that could download and play (execute) Java applets.Hot Java, created by Sun, is simply a browser, much like the Netscape Navigator or Microsoft’s Internet Exploere.Although Hot Java was the first browser to support Java applets, many browsers now support or will soon support applets.Starting with Netscape Navigator 2.0 for example, you can play Java applets for many platforms (Windows 95, the Mac and so on.).Another distinguishing feature of Hot Java is that unlike most browsers which are written in C/C++.Hot Java browser is written with the Java programming language.Q:I followed all the directions you gave for creating a Java applet. I loaded it into HotJava, but Hello World didn’t show up. What did I do wrong?A:Don’t use HotJava to view applets you’ve created in this book; get a more up-to-date browser such as Netscape or Internet Explorer. HotJava was an experimental browser and has not been updated since soon after its original release. The steps you take to define and write an applet have changed since then, and the applets you write now will not run on HotJava.Q:What is static in Java?A:Static means one per class, not one for each object no matter how many instance of a class might exist. This means that you can use them without creating an instance of a class.
Static methods are implicitly final, because overriding is done based on the type of the object and static methods are attached to a class, not an object.
A static method in a superclass can be shadowed by another static method in a sub class, as long as the original method was not declared final.
However, you can’t override a static method with a non static method. In other words, you can’t change a static method into an instance method of a subclass.
Q:Why java does not support pointers?A:Because pointers are unsafe, Java uses reference types to hide pointer and programmers feel easier to deal with reference types without pointers.Q:I’m using Notepad on Windows to edit my Java files. The program insists on adding a .txt extension to all my files, regardless of what I name them (so I always end up with files like HelloWorld.java.txt). Short of renaming them before I compile them, what else can I do to fix this?Q:What is a platform?A:A platform is the hardware or software environment in which a program runs.
Most platforms can be described as a combination of the operating system and hardware, like Windows 2000/XP, Linux, Solaris and MacOs.Q:What is a JVM consists of?A:Each time of a Java Application is executed then an instance of JVM, responsible for its running, is created.
A JVM instance is described in terms of subsystems, memory areas, data types, and instructions.Q:How Java enabled high performance?A:Java uses Just In Time compiler to enable high performance.
Just-In-Time compiler is a program that runs Java bytecode, which is a program that contains instructions that must be interpreted into instructions that can be sent directly to the processor.Q:What is JTI compiler?A:Just In Time compiler: It is used to improve the performance.
JIT compiles parts of the byte code that have similar functionality at the same time, and hence reduces the amount of time needed for compilation.
Here the term compiler refers to translator from the instruction set of a Java virtual machine (JVM) to the instruction set of a specific CPU.Q:What are the supported platforms by Java Programming Languages?A:Java runs on a variety of platforms, such as
Windows
Mac OS and
The various versions of UNIX/Linux like
HP-Unix
Sun Solaris
Redhat Linux
Ubuntu
CentOS etc.
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Tech Jitendra
Tech Jitendra 