Pre-Requirements

What are the things needed before you start Java programming?

        A few software elements are needed before you start writing programs in Java.These are:-

1. Java Development Kit(JDK)--> JDK is bundle of software that you can use to develop Java based   software. 
2. Java Runtime Environment(JRE)--> JRE is an implementation of the Java Virtual Machine which actually executes Java programs. But this is an old procedure of launching programs.  Thus, jre no longer comes with Sun JDK, and instead it has been replaced by this new java loader
3. Text Editor or IDE--> A simple text editor like Notepad(in Windows) or gEdit (in Linux) can be used to write Java program. You can also use an Integrated Development Environment(IDE) like Eclipse or Netbeans. There are some advantages in using an IDE. These are as follows:-

• Quickly navigating to a type without needing to worry about namespace, project etc
• Navigating to members by treating them as hyperlinks
• Autocompletion when you can't remember the names of all members by heart
• Automatic code generation
• Refactoring (massive one)
• Organise imports (automatically adding appropriate imports in Java, using directives in C#)
• Warning-as-you-type (i.e. some errors don't even require a compile cycle)
• Hovering over something to see the docs
• Keeping a view of files, errors/warnings/console/unit tests etc and source code all on the screen at the same time in a useful way
• Ease of running unit tests from the same window
• Integrated debugging
• Integrated source control
• Navigating to where a compile-time error or run-time exception occurred directly from the error details.

What is the difference between JDK & JRE?

       JRE is Java Runtime Environment. The Java programming language adds the portability by converting the source code to byte code version which can be interpreted by the JRE and gets converted to the platform specific executable ones. Thus for different platforms one has corresponding implementation of JRE. But JRE has to meet the specification JVM (Java Virtual Machine) Concept that serves as a link between the Java libraries and the platform specific implementation of JRE. Thus JVM helps in the abstraction of inner implementation from the programmers who make use of libraries for their programmes.
     The JDK(Java Developmental Tool kit) comes along with java libraries and JVM embedded in it. Apart from these it comes along with the utility tools for byte code compilation "javac", Executing the byte codes through java programmes through "java" and many more utilities found in the binary directory of java. Speaking practically JDK is essential for developers, which comes along with library packages to develop Software programmes. While JRE is minimal set of programmes which executes the java class files developed by the software developers.

Download links-->

   JDK (version 7)-->http://www.oracle.com/technetwork/java/javase/downloads/java-se-jdk-7-download-432154.html

   Eclipse IDE--> http://www.eclipse.org/downloads (Note:- Download either Eclipse IDE for Java EE Developers or Eclipse IDE for Java Developers)

   Netbeans IDE-->  http://netbeans.org/downloads/ (Note:- Download the file with the maximum size)

Installing Eclipse IDE:- You only need to download and extract the zip file. No more installation steps are required.

I prefer using Eclipse IDE and will be using the same for my upcoming programs.

If you are ready to write your first Java program after finishing all installations, move on with the next tutorial below.

   

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