1 Java Core Technology Overview

1.1

Java Programming Platform

Java is not just a language, but also a complete platform, with a huge library of reusable code and an execution environment that provides services such as security, portability across operating systems, and automated garbage collection. Java has both a pleasing semantics and a large library to help us implement some of the functions (in fact, code reuse)

One of the advantages of 1.2java

1 Simplicity

2 Object-oriented

3 Network Skills

4 Robustness

5 Security

6 Architecture Neutrality

7 Portability

8 Explanatory type

9 High Performance

Ten Multithreading

Dynamic Nature

1.2.1

Simplicity:java is a pure version of C + + , where there are no header files, pointer operations, structs, unions, operator overloads, virtual base classes .

1.2.2

Object-oriented: This is a programming technique. Focus on the interfaces of the data and objects.

In the carpenter analogy, object-oriented attention is made to the Chair, non-object-oriented attention is the tool used.

1.2.3

Network skills

Java has an extended example libraries for dealing with TCP/IP protocols like Http/ftp, wherejava applications can URLs Open and Access objects on the network as if they were accessing local files (here's a myth)

1.2.4

Robustness

Devote a lot of effort to early problem detection, later dynamic detection, and eliminate the state of error prone, can be detected at compile time some other languages can only be detected at runtime errors.

1.2.5 Security

Java is suitable for network / distributed environments. To achieve this goal, a lot of effort has been devoted to security, and JAVA can be used to build anti-virus tamper-proof systems.

1.2.6 Architecture Neutrality

The compiler generates an architecture-neutral destination file format, which is a compiled code that can run on many processors as long as there is a Java runtime system. the JAVA compiler implements this feature by generating bytecode directives that are independent of the specific computer architecture

1.2.7 Portability

The Java data type has a fixed size and has been explicitly described. Eliminates headaches when porting code.

This means that writing JAVA programs on different operating systems is still a comparative advantage.

1.2.8

Explanatory type

The Java interpreter can execute Java bytecode on any machine that has ported the interpreter .

There are still some things that I don't understand for the time being (read the book later)

1.3 Java applets and the Internet

The idea is simple: users download java bytecode from the Internet and run it on their own machines. Running a Java program on a Web page becomes an applet. in order to use applets , you need to enable Java of the Web The browser executes the byte code.

1.4 Java Development history details see the book

There are three versions of Java

Standard Edition

Miniature version : embedded devices such as mobile phones

Enterprise Edition: User server-side processing

1.5 Common misconceptions about java

1 Java Core Technology Overview