WAR vs EAR for web application with no EJB? - java

I have a Java EE web application that does not make use of EJBs. I am targeting Jetty/Tomcat for deployment some of the time and thus need a WAR packaging. However, I am also target JBoss and Websphere some of the time.
My understanding is that full-blown Java EE application servers can take either EAR or WAR formats. When would I use one over the other and why? I understand they are both standard compressed file formats and I have read 10 different snippets that try to explain them (including this one), but am no closer to understanding the pros and cons of each.

If you have only web modules - use WAR file.
If you have different Java EE modules - use EAR. Though you can deliver only web modules in EAR - there is no point in doing this (and you will need to do more complex deployment configuration)

The crucial point is if you need anything provided in an EAR file (which may contain said WAR file). If so, then it makes sense to deploy as an EAR.
It can also wire up some of the configuration you need to do manually in Tomcat etc. A typical example is the URL bound to the web application, where you need to override the default heuristic with a container specific configuration file for a WAR, but you can put it directly in the EAR configuration file.
Also, during development WARs can frequently be hotdeployed directly in exploded form, where EARs must be unpacked and deployed. For Glassfish from Eclipse the difference is quite noticeable.

In J2EE application, modules are packaged as EAR, JAR and WAR based on their functionality
If You are using only Servlet, JSP, GIF and HTML files. Then use .WAR
WAR:(Web ARchive) Web modules which contain Servlet class files, JSP
Files, supporting files, GIF and HTML files are packaged as JAR file
with .war (web archive) extension.
If you are using different different JAVA EE modules like (EJB + Servlet, JSP, GIF and HTML files + Other technology). Then use .EAR
EAR: (Enterprise ARchive) All above files (.jar and .war) are packaged
as JAR file with .ear (enterprise archive) extension and deployed into
Application Server.

Related

How to create a jar file for a web application using Netbeans IDE 8.0

I did a Web Application using Netbeans IDE 8.0 in JAVA platform. The project consists of JSP's, Servlets and normal .java files. I would like to deploy the project as a simple jar file to the client so that they can execute the jar file and use the application. I am trying to generate jar file using Netbeans with the given resources but there were no proper resources for this. When I tried one of the sources provided, a war file is created rather than a jar file.
So, please help me in converting my web application into a jar file. Also, please let me know why a war file is created for my application rather than a jar file. Also, let me know how to execute war file.
Java applications use jar files and java web-applications use war files. JAR (Java ARchive) is a package file format typically used to aggregate many Java class files and associated metadata and resources (text, images, etc.) into one file to distribute application software or libraries on the Java platform. WAR file (Web application ARchive) is a JAR file used to distribute a collection of JavaServer Pages, Java Servlets, Java classes, XML files, tag libraries, static web pages (HTML and related files) and other resources that together constitute a web application. Since the structure of a web application is very much different from a typical java standalone application you need to deploy it into a war file. To run a WAR file you need a java EE based server like apache tomcat, jboss, glassfish etc. Steps required to run the war file are (One of the solutions possible, although there are many other -as pointed out by boris):-
1.Start the web server;
2.Deploy the war file to the web server;
3.Visit JSP pages or servlets in the browser by entering thier links to their path.
see this link for more details on deploying war :- deploy war file in tomcat server

What are java web application deployment formats?

WAR file is one of the common ways to deploy a java web application. What other deployments formats available for Java Web Applications? What are the differences between them?
Besides WAR, the enterprise applications can be wrapped within the so called "enterprise archive", which extension is ear. Here's a list of the archive types, in which the different pieces of a web-application are wrapped.
JAR: EJB modules which contain enterprise java beans class files and EJB deployment descriptor are packed as JAR file(s) with .jar extenstion
WAR: Web modules which contains Servlet class files, JSP Files, supporting files, GIF and HTML files are packaged as JAR file with .war (web achive) extension
EAR: All above files(.jar and .war) are packaged as JAR file with .ear ( enterprise archive) extension and deployed into Application Server. Contains also third party libraries. Has a special directory called APP-INF that contains the application.xml file descriptor.

How to Deploy Java EE Project which reference external JAR files in weblogic

I have a web application which consist of JSP pages, Servlet and Consumes Web Services.
It also references apache axis and excel libraries.
Now I want to deploy my application directly in Weblogic server
How do i do that.Whcih archive shud i make WAR or JAR??
ALso how to ensures that it covers all the referenced libraries.
I have made my application in Jdeveloper, but I dont want to deploy it using Jdevelper..
I would package my solution as a .war file, containing all dependent .jar files.
That way your solution is self-contained. You can deploy to an app server containing other apps with their own versions of your libraries (dependent or developed). If you put the dependent jars directly into the app server (as you can do), then you're forcing those versions on all applications deployed, and that could well cause you grief.
The downside is that your developed .war file can become sizable. It's not normally a major problem, and I wouldn't worry about it until it's identified as an issue.
A JAR-file cannot contain a JAR-file, so that option is out. Since you mention JSPs and servlets a WAR would seem the appropriate option, although an EAR with a WAR and several JARs could also be a way forward...
Cheers,
Consider a WAR with your JAR files in WEB-INF/lib. Or, create an EAR with APP-INF/lib folder.

When releasing a java spring web application, what are the steps to deploy/release?

If I make a spring mvc application, what are the things I have to do to deploy the application? (say its a commercial application)
What options do I have? Do all applications compress the classes into a .war file?
/WEB-INF/web.xml, appname-servlet.xml, etc.
/WEB-INF/jsp/*.*
/WEB-INF/appname.war ???
Done correctly, the build process will create a war which can be dropped into any servlet container (Tomcat, Jetty, Glassfish).
If you use external source files, those would have to be configured.
If you use advanced features provided by the servlet container, the server would have to configured as well.
Spring application is no different from any java web application when deploying. but generally the only thing I have to do is flip the order of test spring config with the actual one.
Any IDE could create the WAR file for you. As you've said the configuration xml files go to /WEB-INF folder and jsp files (by default) to /WEB-INF/jsp/. You also need to put all required jar files in /WEB-INF/lib folder. Compiled classes will go to /WEB-INF/classes, but let the IDE do that for you.
The war file shouldn't be in the /WEB-INF folder. In Tomcat for example you need to copy it to the webapps folder.

.war vs .ear file

What is the difference between a .war and .ear file?
A WAR (Web Archive) is a module that gets loaded into a Web container of a Java Application Server. A Java Application Server has two containers (runtime environments) - one is a Web container and the other is a EJB container.
The Web container hosts Web applications based on JSP or the Servlets API - designed specifically for web request handling - so more of a request/response style of distributed computing. A Web container requires the Web module to be packaged as a WAR file - that is a special JAR file with a web.xml file in the WEB-INF folder.
An EJB container hosts Enterprise java beans based on the EJB API designed to provide extended business functionality such as declarative transactions, declarative method level security and multiprotocol support - so more of an RPC style of distributed computing. EJB containers require EJB modules to be packaged as JAR files - these have an ejb-jar.xml file in the META-INF folder.
Enterprise applications may consist of one or more modules that can either be Web modules (packaged as a WAR file), EJB modules (packaged as a JAR file), or both of them. Enterprise applications are packaged as EAR files ― these are special JAR files containing an application.xml file in the META-INF folder.
Basically, EAR files are a superset containing WAR files and JAR files. Java Application Servers allow deployment of standalone web modules in a WAR file, though internally, they create EAR files as a wrapper around WAR files. Standalone web containers such as Tomcat and Jetty do not support EAR files ― these are not full-fledged Application servers. Web applications in these containers are to be deployed as WAR files only.
In application servers, EAR files contain configurations such as application security role mapping, EJB reference mapping and context root URL mapping of web modules.
Apart from Web modules and EJB modules, EAR files can also contain connector modules packaged as RAR files and Client modules packaged as JAR files.
From GeekInterview:
In J2EE application, modules are packaged as EAR, JAR, and WAR based on their functionality
JAR:
EJB modules which contain enterprise java beans (class files) and EJB deployment descriptor are packed as JAR files with .jar extension
WAR:
Web modules which contain Servlet class files, JSP Files, supporting files, GIF and HTML files are packaged as a JAR file with .war (web archive) extension
EAR:
All the above files (.jar and .war) are packaged as a JAR file with .ear (enterprise archive) extension and deployed into Application Server.
war - web archive. It is used to deploy web applications according to the servlet standard. It is a jar file containing a special directory called WEB-INF and several files and directories inside it (web.xml, lib, classes) as well as all the HTML, JSP, images, CSS, JavaScript and other resources of the web application
ear - enterprise archive. It is used to deploy enterprise application containing EJBs, web applications, and 3rd party libraries. It is also a jar file, it has a special directory called APP-INF that contains the application.xml file, and it contains jar and war files.
WAR (web archive) files contain servlet class files, JSPs (Java servlet pages), HTML and graphical files, and other supporting files.
EAR (enterprise archive) files contain the WAR files along with the JAR files containing code.
There may be other things in those files but their basically meant for what they sound like they mean: WAR for web-type stuff, EAR for enterprise-type stuff (WARs, code, connectors et al).
JAR Files
A JAR (short for Java Archive) file permits the combination of several
files into a single one. Files with the '.jar'; extension are utilized by
software developers to distribute Java classes and various metadata.
These also hold libraries and resource files, as well as accessory files
(such as property files).
Users can extract and create JAR files with Java Development Kit's
(JDK) '.jar' command. ZIP tools may also be used.
JAR files have optional manifest files. Entries within the manifest file
prescribe the JAR file's use. A 'main' class specification for a file class
denotes the file as a detached or ‘stand-alone' program.
WAR Files
A WAR (or Web Application archive) files can comprise XML
(extensible Markup Language) files, Java classes, as well as Java Server
pages for purposes of Internet application. It is also employed to mark
libraries and Web pages which make up a Web application. Files with
the ‘.war' extension contain the Web app for use with server or JSP (Java
Server Page) containers. It has JSP, HTML (Hypertext Markup
Language), JavaScript, and various files for creating the aforementioned
Web apps.
A WAR file is structured as such to allow for special directories and
files. It may also have a digital signature (much like that of a JAR file)
to show the veracity of the code.
EAR Files
An EAR (Enterprise Archive) file merges JAR and WAR files into a
single archive. These files with the ‘.ear' extension have a directory for
metadata. The modules are packaged into on archive for smooth and
simultaneous operation of the different modules within an app server.
The EAR file also has deployment descriptors (which are XML files)
which effectively dictate the deployment of the different modules.
Refer: http://www.wellho.net/mouth/754_tar-jar-war-ear-sar-files.html
tar (tape archives)
- Format used is file written in serial units of fileName, fileSize, fileData
- no compression. can be huge
Jar (java archive)
- compression techniques used
- generally contains java information like class/java files. But can contain any files and directory structure
war (web application archives)
- similar like jar files only have specific directory structure as per JSP/Servlet spec for deployment purposes
ear (enterprise archives)
- similar like jar files. have directory structure following J2EE requirements so that it can be deployed on J2EE application servers.
- can contain multiple JAR and WAR files
Ear files provide more options to configure the interaction with the application server.
For example: if the hibernate version of the application server is older than the one provided by your dependencies, you can add the following to ear-deployer-jboss-beans.xml for JBOSS to isolate classloaders and avoid conflicts:
<bean name="EARClassLoaderDeployer" class="org.jboss.deployment.EarClassLoaderDeployer">
<property name="isolated">true</property>
</bean>
or to src/main/application/META-INF/jboss-app.xml :
<?xml version="1.0"?>
<jboss-app>
<loader-repository>
loader=nameofyourear.ear
<loader-repository-config>java2ParentDelegation=false</loader-repository-config>
</loader-repository>
</jboss-app>
This will make sure that there is no classloader conflict between your application and the application server.
Normally the classloader mechanism works like this:
When a class loading request is presented to a class loader, it first
asks its parent class loader to fulfill the request. The parent, in
turn, asks its parent for the class until the request reaches the top
of the hierarchy. If the class loader at the top of the hierarchy
cannot fulfill the request, then the child class loader that called it
is responsible for loading the class.
By isolating the classloaders, your ear classloader will not look in the parent (=JBoss / other AS classloader).
As far is I know, this is not possible with war files.
J2EE defines three types of archives:
Java Archives (JAR) A JAR file encapsulates one or more Java classes, a manifest, and a descriptor. JAR files are the lowest level of archive. JAR files are used in J2EE for packaging EJBs and client-side Java Applications.
Web Archives (WAR) WAR files are similar to JAR files, except that they are specifically for web applications made from Servlets, JSPs, and supporting classes.
Enterprise Archives (EAR) ”An EAR file contains all of the components that make up a particular J2EE application.
To make the project transport, deployment made easy.
need to compressed into one file.
JAR (java archive) group of .class files
WAR (web archive) - each war represents one web application
- use only web related technologies like servlet, jsps can be used.
- can run on Tomcat server
- web app developed by web related technologies only jsp servlet html js
- info representation only no transactions.
EAR (enterprise archive) - each ear represents one enterprise application
- we can use anything from j2ee like ejb, jms can happily be used.
- can run on Glassfish like server not on Tomcat server.
- enterprise app devloped by any technology anything from j2ee like all web
app plus ejbs jms etc.
- does transactions with info representation. eg. Bank app, Telecom app

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