Java Environment | Core Java Tutorial

Java Environment:

Before starting how to create Java programs, let us see the environment in which a user can create and execute Java programs. The complete java environment contains two components. They are :

1)JDK :

JDK stands for “Java Development Kit”. It provides the set of tools where the user can compile and execute his programs. These tools include :
javac : This stands for Java compiler. This tool converts a Java source code into its equivalent bytecode.
java : This stands for java interpreter. This tool interprets and executes java bytecode.
jdb : This stands for java debugger. This tool is used to detect errors in a java program.
javap : This stands for java disassembler. It displays the accessible functions and data in a compiled class file.
javah : This tool is used to make C routines that can call Java methods.
javadoc : Creates HTML documentation based on Java source code and the comments it contains.
appletviewer : This tool is used to run applets.
rmic :  Creates class files that support RMI.
rmiregistry : Registry used to gain access to RMI objects on a specific machine.

2) JSL :

JSL stands for “Java Standard Library”. It is also called “API” (Application Programming Interface). This tool provides a set of packages which can be used in Java Programs. A package is a collection of built-in classes which can be imported and used in Java Programs. The following are some of the important API provided by Java Language.
java.lang : Provides classes like System, String ,Thread, Exception etc., for programming Language support.
java.awt : Provides classes for building GUI tools like 2-D drawings, Buttons, Labels etc.,
java.applet : Provides classes that support applets.
java.util : Provides system utility tools like current Date, Calendar, time etc.,
java.net : Provides classes for building networking applications.
java.io : Provides classes for IO programming, File handling etc.,