Java class libraries and common class libraries

Java Class Library Concepts: Java's application Interfaces (APIs) are organized in packages, each of which provides a large number of related classes, interfaces, and exception handling classes, and the collection of these packages is the Java class Library

The package name begins with Java, which is the Java kernel package (Java core packages);

Packages that start with Javax are Java expansion packs (Java Extension package), such as javax.swing packages;

Common Java Core Packages (Java cores package)

1. 1. Java.lang Basic Class library for Java programming language
2. Java.applet all the classes required to create an applet
3. java.awt creating user interfaces and classes for drawing and managing graphics, images
4. java.io system input and output via data stream, object sequence and file system
5. java.net all classes used to implement network communication applications
6. 6. java.util Collection class, Time processing mode, date and time tools and other common tool kits

There are other

1. java.sql accessing and processing classes from Java standard data source data
2. Java.test classes and interfaces for working with text, dates, numbers, and messages in a way that is independent of natural language
3. Java.security Some of the classes needed to design a network security solution
4. Java.beans all the classes needed to develop Java beans
5. Java.math Concise integer arithmetic and basic functions of decimal arithmetic
6. Java.rmi all classes related to remote method calls

Common Java Extensions (Java Extension package)

1. javax.accessibility defines a mechanism for mutual access between user interface components

2. Javax.naming.* provides a series of classes and interfaces for naming services

3. Javax.swing.* provides a series of lightweight user interface components that are commonly used in the current Java UI

Note 1: The most important and commonly used is 1 and 6, has been marked in bold, need to focus on

Note 2: When using Java, other packages require import statements to be used in addition to Java.lang.

Main content: Java.lang and Java.util.

java.lang bag

This package, called the Java language Pack, is introduced automatically by the compiler. It is not necessary to use the import statement in the program. It contains classes and interfaces that are necessary for all actual Java programs.

1. Object class
2. Math Class (Math)
3. Data type class
4. Thread class
5. String Class (String class and StringBuffer Class)
6. Systems and Runtime classes (System class and runtime Class)
7. Error and exception handling classes (Throwable, Exception, error)
8. Procedure Class (process)

java.util bag

1. Date classes, calendar classes (Data, calendars, GregorianCalendar)

2. Random number classes (randomness)

3. Bit operation Class (BitSet)

4. Vector classes (vectors)

5. Data structure Class (Stack)

6. Hash List class (Hashtable)

7. StringTokenizer Class

Referenced from: http://blog.csdn.net/zccst/article/details/5070334

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Java class libraries and common class libraries