Differences between J2EE, j2se, and j2s

Differences between J2EE, j2se, and j2s

This article briefly introduces the concepts and differences between J2EE, j2se, and j2se. J2EE, j2se, and j2se provide different services for different Java applications, that is, provide different types of class libraries.

The Java2 Platform consists of three versions: Standard Edition (j2se), Enterprise Edition (J2EE), and mini version (j2se:
J2se (Java 2 Standard Edition) is the Java 2 Standard Edition. It is mainly used for programming desktop applications.
J2EE (Java2 Enterprise Edition) is the Enterprise Edition of Java2. It is mainly used for the development of distributed network programs, such as e-commerce websites and ERP systems.
Java 2 Micro Edition is a micro version of Java. It is mainly used in embedded system development, such as mobile phone and PDA programming.

Standard Edition (Standard Edition) j2se Contains classes that constitute the core of the Java language. For example, database connection, interface definition, input/output, and network programming
Enterprise Edition (Enterprise Edition) J2EE Contains classes in j2se and also the classes used to develop enterprise-level applications. For example: EJB, Servlet, JSP, XML, transaction control
Micro Edition (miniature edition) j2se contains a class of j2se for software development of consumer electronic products. For example, pager, smart card, mobile phone, PDA, and set-top box

 

In general, we can understand it as follows:

J2se is the Foundation;
One point of compression, and some other cldc features are added;
One more step is to add some enterprise applications such as EJB, Which is J2EE.

Their scope is: j2se is included in J2EE, and j2se contains the j2se core class, but some new proprietary classes are added.

 

For beginners, they all start with j2se.

Differences between J2EE and j2se:
J2EE adds a series of enterprise-level application programming interfaces on the basis of j2se. J2EE contains many technologies! Among them, you are familiar with JSP, Servlet, JDBC, jme and other 13 technology!
J2EE is mainly used for B/S structure applications! That is to say, it is based on browsers and servers!
J2se gives me the feeling that only one container is enough. J2EE supports distributed components and multiple containers can exist at the same time.

1. What is J2EE?
J2EE is a standard proposed by Sun. The product that complies with this standard is called "implementation". The J2EE development package of sun you downloaded has such an "implementation ", JBoss, WebLogic, and WebSphere are all "implementations" of the J2EE standard ". Because JBoss, WebLogic, and WebSphere have J2EE APIs, sun's J2EE implementation is not required. For more information about J2EE, see J2EE architecture.

2. Differences between j2eesdk and j2sdkee
In fact, you can regard j2eesdk and j2sdkee as the same thing. The official name is j2eesdk. However, if you think carefully, you can use the following method to understand: j2eesdk is JDK, which must be installed for development of ejg. j2sdkee is a J2EE development environment (common development environment mode: SERVER + database + integrated development environment, such as MySQL + Tomcat + myeclipse), this is also to be installed. In fact, if you have installed JBoss, you do not need to install j2sdkee all, you just need to copy one of the files named J2EE, that is to say, JDK must be installed, but j2sdkee does not need to, depending on what you are using as a container.

3. Do I still need to install j2sesdk if I have installed j2eesdk?
When you download j2ee1.4 on Sun's website, there are two download packages:
◆ One is the complete j2ee1.4sdk package (allinone), including j2eeserver, j2se, sample, apidoc; J2EE seems to contain almost everything j2se. I think there is also a JDK in J2EE. The LIB below is as big as the Lib below j2se (same version ). but the JRE is not big, because J2EE is much more than j2se, such as Java. servlet. *, Java. servlet. HTTP.. j2EE is something that allows you to develop j2eespecification. for a Web server, do not install J2EE. You only need to install a JRE (not even j2se) and a Servlet Engine (such as Tomcat. take a look at the following:
J2sew.jdk1_bin1_demo1_demo1_jre1_lib1_src.rar // Sun's official jdk1.4.2
J2EE = JDK +... // The JDK here is not as big as the JRE File above. The reason is as mentioned above.

◆ The other is a separate j2eeserver. You need to install j2sesdk before installation.
After installation, you must set the java_home, j2ee_home, and classpath environment variables and run j2eeserver.
To facilitate developers, Sun divides Java into j2se (java2standardedition), java2javasiseedition, java2microedition, and javacard. J2se is the foundation of all Java technologies. No matter what platform Java applications developers need to develop, they must first learn from j2se. The J2EE Technology focuses on Enterprise Server applications. Mainly for embedded systems, such as mobile phones and PDAs. Sun also provides a free j2mewirelesstoolkit for mobile app development. Javacard technology is used to develop applications that can be implanted into IC smart cards.

 

From: https://www.cnblogs.com/HDK2016/p/6128492.html

Differences between J2EE, j2se, and j2s