Java Programming - JAVA Programming for Engineers - page 6

library additions. The core libraries must be present in every implementa-
tionofJava,whiletheoptionallibrariescanbepresentornot.However,ifa
featureinanoptionallibraryissupportedinaparticularimplementation,it
must be fully supported in the standard way.

The complexity of the Java libraries can intimidate a beginning pro-
grammer. In the current version of the Java Development Kit (JDK), there
are12corelibraries. Table1-1 liststhecoreJavalibraries.
Table 1-1
Core Java Libraries

NAME CLASSES DESCRIPTION

java.lang 93 Basic runtime support for the Java

language

java.applet 4 Applets support

Java.awt 298 Windowing and GUI support

javax.swing 500 Supplements java.awt and improves

GUI support

java.io 75 Supports input and output

java.util 77 Utility data structures

java.rmi 65 Remote method calls

java.sql 26 Supports Java Database

Connectivity

java.security 106 Supports secure data coding and

decoding

java.net 38 TCP/IP, UDP, IP, and othernetwork

support

java.beans 43 Component software support to

promote rapid application
development by reuse of existing
code fragments

java.text 50 Support for localized text elements

such as dates, time, and currency

java.math 2 Support for the DECIMAL and

NUMERIC types in the SQL
database. Do not confuse with
java.lang.Math class

javax.accessibility 14 Supports large text sizes for the

visually impaired

Java is an interpreted language
A Java program is executed by an application called the Java interpreter
that must be installed in the host system. The Java interpreter is named
Java. The interpreter reads the code contained in a file produced by the
Java compiler, called Javac. This compiler, in turn, reads a source file writ-
tenintheJavaprogramminglanguage.Theresultofthecompilationstepis
afileusuallycalledthe Java byte code .TheJavasourcefile,whichservesas