JAVA ENVIRONMENTJDK, API, JVM

JAVA ENVIRONMENT

Java environment includes development tools and many classes and methods.

Java EnvironmentJava Environment

JDK JDK (Java Development (Java Development

Kit)Kit)

JSL JSL (Java Standard Library)(Java Standard Library)

or Application Programming or Application Programming Interface (API)Interface (API)

Development Development toolstools

Classes and Classes and methodsmethods

JDK(JAVA DEVELOPMENT KIT)(JAVA DEVELOPMENT KIT)

JDK is collection of tools used for developing and running Java programs.

They include

  appletviewer - for viewing Java applets

javac - Java compiler which translates Java source code to byte code files that the interpreter can understand

java - Java interpreter which runs applets & applications by interpreting byte codes.

javadoc - Creates HTML format documentation from Java source code files

javah - Produces header files for use with methods

jdb - Java debugger, which helps to find errors in programs

 

These tools are used to build and run application programs.

a) To create a java program, create a source file using ___________

 

b) The source code is compiled using _________to ____________

 

c) The byte code is interpreted using ____________ and executed.

 

d) The jdb is used to find ______________, if any.

APIAPPLICATION PROGRAMMING INTERFACE

The API includes hundreds of classes and methods grouped into several packages.

Commonly used packages are:

java.lang Language Support Package - required for basic features of Java

jJava.util Utilities Package - classes that provide functions like date and time functions

java.io Input/Output Package - classes required for input/output

javax.swing Swing Package - common GUI elements like dialog box

java.net Networking Package - classes for communicating with other computers through network

java.awt AWT Package - classes that allow GUI elements and graphics

java.applet Applet Package - classes that allows to create Java applets

JVMJAVA VIRTUAL MACHINE

Byte code is generated for Java Virtual machine.

JVM is not a machine but a program that resides in computer memory.

The byte code is common for all machines.

Java interpreter acts as a link between particular machine and byte code to make machine code (machine language).

Java Program

Java Compiler Virtual Machine

Byte code Java Interpreter Machine code

Byte code

Virtual machine

EXERCISE

Classes and methods of Java are part of

a) JSL

b) JDK

c) JVM

EXERCISE

The tool that is present in JDK is used for viewing Java applets

a) applet viewer

b) applet

c) javac

EXERCISE

EXERCISE

The Java debugger, which helps to find errors in programs is

a) javadoc

b) jdb

c) javah

The package which has classes for communicating with other computers through network

a) Input/Output package

b) AWT package

c) Networking package