Some problems that J2EE beginners will encounter

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.
2. Differences between j2ee sdk and j2sdkee
In fact, you can regard the j2ee sdk and j2sdkee as the same thing. The official name is The j2ee sdk. 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, which also needs to be installed, in fact, if you have installed jboss, you don't need to install j2sdkee all. You just need to copy one of the files named j2ee, that is, jdk must be installed, j2sdkee does not need to be used as a container.
3. Do I still need to install j2se sdk if I have installed j2ee sdk?
When you download J2ee1.4 on sun's website, there are two download packages:
One is the complete j2ee1.4 sdk package (all in one), which includes j2ee server, j2se, sample, and api doc. j2ee seems to contain almost everything in 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 j2ee specification. 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:
J2se = jdk = bin + demo + include + jre + lib + 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 j2ee server. You must install the j2se sdk before installation.
After installation, you must set the java_home, j2ee_home, and classpath environment variables before running the j2ee server.