JAVA: JAVA ENVIRONMENT.

JAVA

Before we start developing a program or executing a program, we should be knowing the environment it has.

Java environment include a large number of developing tools and it also has many number of classes and methods to perform an operation.

classes- user defined blueprint form which an object is created.

method - collection of statement  to perform an operation.

There are three main Java environment we should know.

1. JAVA DEVELOPMENT KIT [JDK].

           The development tool of the system is called Java Development Kit. It has a collection of tool that are used for developing and running the program.

Tools we use are:

• Applet viewer, this tool is used to run java applets, a small java program for internet application.
• Java c, it is known as the java compiler, it is used to translate source code into byte-code.
• Java, it is known as java interpreter, it is used to run applets(a small java program for internet application) and application(a program which has specific task like evaluate equations,read and write etc...)
• Java doc, using this tool we can create HTML format document from java source code.
• java h, using this tool we can produce header-file that is, already declared symbols for use with Native method.

Java doesn't contain header-file, but some time java interface with the system call or library written in other language like C and C++. This is known as native method, so we use java h.

• java p, it is known as Java disassembler tool, which helps us to convert byte-code files back to source code.
• jbd, it is known as Java debugger, which helps to find the errors.

2. APPLICATION PROGRAMMING INTERFACE (API).

                 It is also known has java standalone library. It has large number of classes and methods classified and grouped into several functional packages.

  We mostly use the following packages.

• java.lang, it is known as Language Supporting Package . A collection of classes and methods required for implementing basic features of java.
• java.util, it is known as Utility Packages. A collection of classes to provide utility function such as date and time function.
• java.io, it is also known as Input/output Package. A collection of classes required for input and output manipulation.
• java.net, it is known as Networking Package. A collection of classes for communicating  with other computer via internet.
• java.awt, it is known as Abstract Window Tool kit package, it contains classes that implement platform-independent graphical user interface.
• java.applet, it is known as Applet Package. This includes a set of classes that allows us to create java applets. 

3. JAVA RUNTIME ENVIRONMENT.

                As java application is developed by Java development kit. Java Runtime provide the requirement for executing or running the program.

  The major components of Java Runtime environment are,

• Class Loader.
• Byte-code verifier.
• Java virtual machine (JVM).
• Just In Time compiler (JIT).

Class Loader.

         It loads all the class files required for executing the program.

Byte-code verifier.

         It verifies byte-code to see any security problem are there. It checks for an unauthorized access, if any stack overflow, JVM specifications, illegal data codes etc...

Java virtual machine (JVM).

          It translates the byte-code into the machine understandable language known as machine code, it is also in the form of binary.

Just In Time compiler (JIT).

       JVM process which generates machine code is slow to execute, to overcome this, Java Runtime Environment has JIT, JIT converts the general machine code to native machine code, which can be directly executed by the machine in which java program runs.

These are the important Environment which will be used in developing the program and also executing the program.

Check out the interesting history of Java.

Also the important features of java.