sun's application server?

Question

in a tutorial they asked me to install the application server which could be downloaded from their site.

what do they mean with application server?

the link they provided: http://java.sun.com/javaee/downloads/index.jsp

i mean come on sun, all these names. jdk then j2ee..and when i wanna download j2se it says jdk6. r they insane? a lot of people are wondering what is what...they just dont know how to name things.

however, back to the question. so with application they mean java ee server?

i've got a mac and people say java is already installed. what is installed exactly? the j2ee or j2se? do i have do download j2ee? Java is just killing me...

EDIT: read something about that the application server is a name for ee server. and there are many ee servers like tomcat, jetty and glassfish. and i know these sometimes are called servlet containers.

so that makes application server = ee server = servlet container?

and jdk = j2se? so j2ee != jdk?

Answer 1

Sun's Application Server has been superseded by the community app server, GlassFish.

The JavaEE download page only has two JavaEE6 download links and both contain versions GlassFish v3. Chances are you only need the web profile, but download the full version if you aren't sure.

Note that GlassFish is just the reference Application Server. You also have other Application servers, such as Apache Geronimo and Oracle Weblogic... as well as ones that are just servlet containers, like Apache Tomcat and Jetty. These types should correspond to GlassFish's normal and web profiles respectively.

These other servers only require a JRE to run applications, or the JDK to develop for them.

Side Note: GlassFish v3 is the only JavaEE 6-compliant server... JavaEE 6 is brand new. The others should be JavaEE 5 compliant.

Also, JavaEE is the new name for J2EE, as sun tries to move away from the Java 2 name.

Answer 2

In order to run you Java EE applications you need an application server. The link you provided is to download GlassFish that is one application server.

There are others application servers like Apache Tomcat, Jboss.

JDK stands for Java Development Kit You need this to develop Java applications.

JRE stands for Java Runtime Environment You need this to run Java applications.

Answer 3

GlassFish with the Java EE SDK (provided on the link you gave) is what you need. Java EE server = application server.

What is installed on your Mac by default is probably only a JRE (runtime environment) and not a JDK (development kit). Which means, you can run Java apps but not develop. By downloading GlassFish with the Java EE SDK, you'll get the full-blown SDK you need and a server to deploy on.

Hope that helps.

Answer 4

What do they mean with application server? The link they provided: http://java.sun.com/javaee/downloads/index.jsp

An application server is a component-based middleware used in server centric N-tier architecture. It manages the life-cycle of components deployed on it, it provides services for state maintenance, data access (with pooling of resources), security, clustering and fail-over.

AFAIK, one of the first application server (as just defined above) was ATG Dynamo. Other proprietary application servers include BroadVision, ColdFusion, etc. But none of them really survived to the advent of Java application servers (understand application servers based on the standards defined by Java EE and the Java language).

I mean come on sun, all these names. (...)

Wikipedia does a pretty good job at defining what Java SE is:

Java Platform, Standard Edition or Java SE is a widely used platform for programming in the Java language. It is the Java Platform used to deploy portable applications for general use. In practical terms, Java SE consists of a virtual machine, which must be used to run Java programs, together with a set of libraries (or "packages") needed to allow the use of file systems, networks, graphical interfaces, and so on, from within those programs.

The JRE (Java Runtime Environment) provides the virtual machine and the set of libraries i.e. everything you need to run Java software. The JDK (Java Development Kit) provides a JRE plus a compiler (javac) and some other tools i.e. everything you need to run and develop Java software.

Java EE is a specification (more precisely, a set of specifications) built on top of the libraries provided by Java SE and is more server-side oriented. Implementations of this specification are provided by Java application servers: GlassFish is Sun's implementation, JBoss is RedHat's implementation, WebLogic is BEA Oracle's implementation, WebSphere is IBM's implementation, etc.

Regarding the versions and nomenclature, yes, Sun is crazy. It was an horrible mistake to introduce this "Java 2 Platform, Standard Edition" naming when the version 1.2 came out. I can imagine how confusing this is. But, again, Wikipedia does a great job at clarifying this in the section Nomenclature, standards and specifications:

Java SE was known as Java 2 Platform, Standard Edition or J2SE from version 1.2 until version 1.5. The "SE" is used to distinguish the base platform from Java EE and Java ME. The "2" was originally intended to emphasize the major changes introduced in version 1.2, but was removed in version 1.6. The naming convention has been changed several times over the Java version history. (...)

This should make things more clear.

(...) however, back to the question. so with application server they mean java ee server?

Yes, this is what they mean or, more precisely, they mean Sun GlassFish Enterprise Server (previously named Sun Java System Application Server). Source: http://developers.sun.com/appserver/.

I've got a mac and people say java is already installed. what is installed exactly? the j2ee or j2se? do i have do download j2ee? Java is just killing me...

A JRE or a JDK (if javac available, it's a JDK), so only the Java SE part. And actually, if you are still following me, you don't download Java EE, you download something providing an implementation of it (i.e. an application server).

(...) so that makes application server = ee server = servlet container?

No. To simplify, a Java EE server = Servlet container + EJB Container. Some server are only Servlet container (like Tomcat, Jetty), they don't provide the EJB container part and thus don't fully implement the Java EE specification and can't be considered as full Java EE servers.

and jdk = j2se? so j2ee != jdk?

I hope I covered this with my answer.