Package categories in Java

Package categories in Java

Package categories in Java

Package categories in Java

Package categories in Java

Package categories in Java

     

Java supports two types of packages as shown below in the hierarchy structure:

Build-In Packages in Core Java:

Java packages can be categorized in the hierarchy structure shown as:

Packages in the Java language begin with "java" or "javax" as we can found in both hierarchy structure shown above. Note that, the package "java" also has subpackages in which the package "awt" is further has a subpackage called "event" that is imported to access classes and interfaces to handle the events fired on the awt-component in a program. Thus the the expression to import the package is shown as"

import awt.event.*; 

Lets understand these java packages shown in the table, from which you can access interfaces and classes.

 Package Name  Description
 java.lang It contains essential classes that represent primitive data types (such as int & char) 
as well as more complex classes, including numerics, strings, objects, compiler, 
runtime, security, and threads. This is the only package that is automatically imported
 into every Java program.
 java.io This package provides classes to manage input and output streams to read data from
 and write data to files, strings, and other sources.
 java.util It contains miscellaneous utility classes, including generic data structures, bit sets, time,
 date, string manipulation, random number generation, system properties, notification,
 and enumeration of data structures.
 java.awt It provides an integrated set of classes to manage user interface components such as 
windows, dialog boxes, buttons, checkboxes, lists, menus, scrollbars, and text fields. 
 java.net It provides classes for network support, including URLs, TCP sockets, UDP sockets,
 IP addresses, and a binary-to-text converter.
 java.applet It enables the programmer to create applets through the Applet class. It also provides
 several interfaces that connect an applet to its document and to resources for playing audio.
 java.nio This package handles New I/O framework for Java  
 java.math This package includes various mathematical operations.
 java.security It is used for key generation, encryption and decryption.
 javax.swing It is used for hierarchy of packages for platform-independent rich GUI components.
 java.sql It provides classes to support connectivity from JDBC to access databases