9.2 Java API package
An Application Programming Interface (API), in the context of Java, is a collection of prewritten packages, classes, and interfaces with their respective methods, fields and constructors.
Similar to a user interface, which facilitates interaction between humans and computers, an API serves as a software program interface facilitating interaction.
In Java, most basic programming tasks are performed by the API’s classes and packages, which are helpful in minimizing the number of lines written within pieces of code.
Java system packages and their classes:
java.lang
language support classes.They include classes for primitive types, strings,math functions,threads and exceptions.
java.util
Language utility classes such as vectors, hash tables, random numbers, date etc.
java.io
Input/Output support classes. They provides facilities for the input and output of data.
java.awt
Set of classes for implementing graphical user interface.They include classes for windows, buttons, lists, menus and so on.
java.net
classes for networking. They include classes for communicating with local computers as well as with internet servers.
java.applet
Classes for creating and implement?ing applets.
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