A brief history of Java development
In 1991, James Gosling, a team of engineers at Sun, wanted to design such a small computer language. The language is used primarily for consumer electronics such as TV boxes, which have a common feature: Computational processing power and memory are very limited.
So ask:
The language must be very small and generate very compact code so that it can be executed in such an environment.
In addition, because different vendors choose different CPUs, it is required that the language cannot be tied to a particular architecture, requiring that the language itself be neutral, that is, cross-platform .
So, name this language "green", similar to the meaning of green software.
Later, renaming will oak. The meaning of the oak.
Renamed after found that there is already a language called the name, and then changed to name Java.
In 1991, Sun's Green project, Oak
1995, Java Beta release
1996, JDK1.0
1997, JDK1.1
1998, JDK1.2, greatly improved the previous version of the flaw, is a revolutionary version, renamed to JAVA2.
2004, J2SE 5.0 (1.5.0) Tiger Tigers
2006, J2SE 6.0 (1.6.0) Mustang Mustang
Why Java is popular
C + + is already a perfect object-oriented programming language with all object-oriented features, and C is highly efficient and concise, and therefore very popular. Until now it is still widely used.
However, with the development of the Internet explosion, the development of Java has been promoted.
Although the development of the Internet is a major factor in Java development.
However, the original intention of the invention of Java is for consumer electronics products,
For example: microwave ovens, remote control, etc., for the programming of these products.
Because the CPUs of these products are completely different, and the computing power is very limited and the memory is very limited.
As a result, we need the Java language to meet two features:
System neutrality: Java needs to be able to generate code that runs in different environments and with different CPUs. That is, the portability of the code.
code compact: because he has very limited operating environment resources
java can only be useful but obscure at first.
overnight, Everyone is talking about inertnet,
are busy connecting their computers to the Internet.
this time, there was a big problem.
It's less efficient to transfer information between networks, so it also requires code compactness to improve efficiency.
The Java team suddenly found out that their use of small-scale languages also adapted to the environment of the Internet.
As a result, they shifted their research focus from consumer electronics to Internet programming.
Java is most affected by C #, a Microsoft-launched and Java-counter language to support the. NET Framework. C # is very similar to Java in general.
What the Java versions mean
j2ee (Java 2 Enterprise Edition) : Locate the application on the server side
J2EE is an extension of J2SE, adding a class library for server development.
JDBC is to allow the program personnel to use in Java directly in the SQL syntax to access data in the database,
servlet can extend the functionality of the server, The request-response mode is used to process the client's request;
jsp is a technique that embeds Java program code inside a Web page;
J2SE (Java 2 standard Edition): Applications for positioning on personal computers
This version is the core of the Java platform and provides a very rich API to develop applications on general personal computers, including user interface AWT and swing, network functions and internationalization, image processing capabilities, and input and output support.
The applets that shine on the internet also belong to this version.
J2ME (Java Micro Edition): positioning in the application of consumer electronic products
J2ME is an extension of J2SE, containing part of the J2SE core class,
It also has its own extension class, which adds a class library for tiny devices: javax.microedition.io.*, etc.
This edition streamlines the core class library for the needs of resource-constrained e-consumer products,
and provides a modular architecture to enable different types of products to increase support at any time.
This version of the application level is quite extensive, will be the future development of the Java Platform key projects.
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1.1-java so popular, you know why?!