The most common Java package

The most common Java package

1. java. lang package: the Core class library of Java, including running JavaProgramEssential System classes, such as basic data types, basic mathematical functions, and strings
The system loads the package by default.
2. java. Io package: standard input/output class library of Java language, such as basic input/output stream, file input/output, filter input/output stream, etc.
3. java. util package: contains the date class for processing time, the vector class for processing to an array, and the stack and hashtable classes.

4、java.util.zip package: Implements File compression.
5. java. Lang. Reflect package: provides a tool for reflecting objects
6. java. AWT. Image package: Java tool library for processing and manipulating images from the Internet
7. java. Wat. Peer package: rarely used directly in programs, so that the same Java program runs on different software and hardware platforms
8. java. Applet package
9. java.net package: class libraries that implement network functions include socket and serversocket.
10. java. CORBA package and Java. CORBA. Orb package
11. java. AWT. datatransfer package: tool class for processing data transmission, including clipboard and string Transmitter

12. java. AWT package: Class Library for creating graphical user interfaces (GUI), graphics class for low-level drawing operations, graphical interface components, and layout management such
Checkbox class, container class, layoutmanger interface, and interface user interaction control and event response, such as event class
13. java. AWT. Event package: Gui Event Processing Package.
14. java. SQL package: implement a JDBC class library

All work is required
Java. LANG: Isn't that necessary? Basic
Java. util: tool Library

Skills
Java.net: Protocol package for network communication
Java. IO: Input and Output Pipelines

For GUI
Java. AWT: basic graphic Toolkit
Javax. Swing: advanced graphic Toolkit

For science and finanse
Java. Math: Mathematical expansion package

Database
Java. SQL: the package used to access data source
Javax. SQL: SQL package

Attention and attention
Java. Nio: Native Io package, efficient Io package
Java. util. Concurrent: used to write Multithreading
Java. util. RegEx: Regular Expressions are good.

This is common. Should it be said that it accounts for 80% of the actual application?

More specialized packages, such as XML, ImageIO, and security. Are not commonly used.

The packages in J2EE are basically used for web development.

in addition to the j2se packages, the packages in Apache common should also be checked out, which is very practical.