I know that Tomcat is a web server but why it is not an application server?
Any server needs to follow some specification. What is that spec?
Is it possible for apache to make the tomcat application server?
Also I have read in a blog that the tomcat do not have some lib to act as an application server. What are those libs?
Thanks
I've heard once the following explanation I tend to agree with:
There is a spec of JEE (Java enterprise edition).
Formally you can think about it as a bunch of pdf-s describing the behavior of various technologies that comprise the JEE stack (for example: JMS, EJB, JPA, JPA, JSF, CDI and so on and so forth) as well as deployment models (EARs for example).
Implementors of Application servers have to implement all those technologies and offer interfaces that can be used by the application developers. So teams that stand behind WildFly (former JBoss), Geronimo, WebSphere, WebLogic and so on have read these specs and implemented everything in there.
Now, Tomcat didn't do that, they've only concentrated on (primarily) Servlets/JSPs. These are web technologies, so Tomcat can't be considered as an Application server that implements the whole JEE stack.
In general Tomcat (as well as Jetty, incidentally) should be more lightweight than full JEE compliant Application servers, it should start-up faster and it memory footprint should be smaller. So Tomcat/Jetty call themselves web servers.
I understand that this answer can be considered as speculation, but for me it makes a lot of sense.
Bellow is my perceive:
know that Tomcat is a web server but why it is not an application server?
Here, Application Server is specially for Java EE Server，Java EE is a huge specific collections for Enterprice Application Development，So Application Server should implement most specifics of these, while Tomcat(or Jetty) is only a Web Server(More accurately，Servlet Container)，they only implements the specific about Web(such as Servlet Spec(JSR340), JSP(JSR245)). Therefore，Application Server is stronger than Web Server，but Web Server is more lightweight and enough to satisfy most web applications.
Any server needs to follow some specification. What is that spec?
Of course，it depends on that your Server want to provide what services(functions)，these specifications can view here.
Is it possible for apache to make the tomcat application server?
I don't think apache will make tomcat to be an application server. Now, there are some popular Java EE Server: Jboss，WebLogic, etc. Not all enterprices need a heavyweight Application Server, on the contrary, most only need a lightweight Web Server。
Also I have read in a blog that the tomcat do not have some lib to act as an application server. What are those libs?
Tomcat only need care the specs about Web，and implements them.
Hope for your help.
Related
Can I deploy a Spring java application on all (or at least most) of JavaEE servers ? like Weblogic, JBoss, Webshpere, Tomcat, Jettty etc.
And is there is preferred Java EE server for Spring ?
Yes you can. And no - there isn´t. Errata: you can take a look at the SpringSource dm Server. Be aware that spring is not a java EE implementation. Read this post here.
Yes, you can deploy it on any server, and you can use it on standalone applications and even on mobile applications. It is in no way restricted to web deployment. It is not even restricted to java, there is Spring.NET and even a Python version. However, java and web servers are a common if not the most common use for it.
Currently recommended web server by VMWare/Pivotal (current owner of Spring) is VFabric tcServer, which is a Tomcat fork containing some extra tools and functionality. But server in itself does not matter, Spring is container agnostic.
There is no preferred EE server. VFabric tcServer is a servlet container, not an EE server. It contains "enterprise capabilities" instead, but that's not the same thing. As said however, you can use whichever EE server you want.
I'm starting to learn spring and I came across one definition which says "Spring enables developers to do enterprise development without an application server".
What does this exactly mean and what's the harm in using an application server for enterprise development.
But don't developers use tomcat while developing enterprise development and isn't Tomcat an application server.
I'm confused here.
Can someone clarify the two points mentioned above.
I think what's meant by "Spring enables developers to do enterprise development without an application server", is that you don't need a full Java EE application server like JBoss, WebLocic, WebSphere ... but can do everything with a 'simple' servlet container like Tomcat.
Springframework provides services like dependency injection, declarative transaction management and others which are provided by Java Application Server for Java EE applications. The difference is that Spring based app can work standalone while Java EE app can't. It may be the reason to favor Springframework over a Java AS.
Tomcat is a servlet container which implements only Servlet and JavaServer Pages specifications, Java Application Server is supposed to support all of Java EE specifications like EJB, JMS, JPA, JTA and many others
I am starting to look into Enterprise Java and the book I am following mentions that it will use JBoss. Netbeans ships with Glassfish. I have used Tomcat in the past.
What are the differences between these three programs?
Tomcat is just a servlet container, i.e. it implements only the servlets and JSP specification. Glassfish and JBoss are full Java EE servers (including stuff like EJB, JMS, ...), with Glassfish being the reference implementation of the latest Java EE 6 stack, but JBoss in 2010 was not fully supporting it yet.
Tomcat is merely an HTTP server and Java servlet container. JBoss and GlassFish are full-blown Java EE application servers, including an EJB container and all the other features of that stack. On the other hand, Tomcat has a lighter memory footprint (~60-70 MB), while those Java EE servers weigh in at hundreds of megs. Tomcat is very popular for simple web applications, or applications using frameworks such as Spring that do not require a full Java EE server. Administration of a Tomcat server is arguably easier, as there are fewer moving parts.
However, for applications that do require a full Java EE stack (or at least more pieces that could easily be bolted-on to Tomcat)... JBoss and GlassFish are two of the most popular open source offerings (the third one is Apache Geronimo, upon which the free version of IBM WebSphere is built). JBoss has a larger and deeper user community, and a more mature codebase. However, JBoss lags significantly behind GlassFish in implementing the current Java EE specs. Also, for those who prefer a GUI-based admin system... GlassFish's admin console is extremely slick, whereas most administration in JBoss is done with a command-line and text editor. GlassFish comes straight from Sun/Oracle, with all the advantages that can offer. JBoss is NOT under the control of Sun/Oracle, with all the advantages THAT can offer.
You should use GlassFish for Java EE enterprise applications.
Some things to consider:
A web Server means: Handling HTTP requests (usually from
browsers).
A Servlet Container (e.g. Tomcat) means: It can handle
servlets & JSP.
An Application Server (e.g. GlassFish) means: *It can manage
Java EE applications (usually both servlet/JSP and EJBs).
Tomcat - is run by Apache community - Open source and has two flavors:
Tomcat - Web profile - lightweight which is only servlet container and does not support Java EE features like EJB, JMS etc.
Tomcat EE - This is a certified Java EE container, this supports all Java EE technologies.
No commercial support available (only community support)
JBoss - Run by RedHat
This is a full-stack support for JavaEE and it is a certified Java EE container.
This includes Tomcat as web container internally.
This also has two flavors:
Community version called Application Server (AS) - this will have only community support.
Enterprise Application Server (EAP) - For this, you can have a subscription-based license (It's based on the number of Cores you have on your servers.)
Glassfish - Run by Oracle
This is also a full stack certified Java EE Container. This has its own web container (not Tomcat).
This comes from Oracle itself, so all new specs will be tested and implemented with Glassfish first. So, always it would support the latest spec. I am not aware of its support models.
jboss and glassfish include a servlet container(like tomcat), however the two application servers (jboss and glassfish) also provide a bean container (and a few other things aswell I imagine)
It seems a bit discouraging to use Tomcat when you read these answers. However what most fail to mention is that you can get to identical or almost identical use cases with tomcat but that requires you to add the libraries needed (through Maven or whatever include system you use).
I have been running tomcat with JPA, EJBs with very small configuration efforts.
JBoss and Glassfish are basically full Java EE Application Server whereas Tomcat is only a Servlet container.
The main difference between JBoss, Glassfish but also WebSphere, WebLogic and so on respect to Tomcat but also Jetty, was in the functionality that an full app server offer. When you had a full stack Java EE app server you can benefit of all the implementation of the vendor of your choice, and you can benefit of EJB, JTA, CDI(JAVA EE 6+), JPA, JSF, JSP/Servlet of course and so on. With Tomcat on the other hands you can benefit only of JSP/Servlet. However to day with advanced Framework such as Spring and Guice, many of the main advantage of using an a full stack application server can be mitigate, and with the assumption of a one of this framework manly with Spring Ecosystem, you can benefit of many sub project that in the my work experience let me to left the use of a full stack app server in favour of lightweight app server like tomcat.
Both JBoss and Tomcat are Java servlet application servers, but JBoss is a whole lot more. The substantial difference between the two is that JBoss provides a full Java Enterprise Edition (Java EE) stack, including Enterprise JavaBeans and many other technologies that are useful for developers working on enterprise Java applications.
Tomcat is much more limited. One way to think of it is that JBoss is a Java EE stack that includes a servlet container and web server, whereas Tomcat, for the most part, is a servlet container and web server.
Apache tomcat is just an only serverlet container it does not support for Enterprise Java application(JEE). JBoss and Glassfish are supporting for JEE application but Glassfish much heavy than JBOSS server : Reference Slide
I am currently developing an application for some researchers in my university.It's a small java program that you can use by command line. The next step is to package that program and deploy it to an application server. Some clients program will submit requests to the server who will call the tool that I wrote. Lately, we will add more tools to the server and he has to dispatch the requests to the right tool.
Which application server fits my needs ? I have looked for Tomcat, Jetty and Glassfish but it seems that they are only used for web application.
Is it possible to use those servers in some context different from web context? Which package archive should i use (jar, war) ?
Any advice?
Some clients program will submit requests to the server who will call the tool that I wrote.
The big question is what server-side technology and what communication protocol can you use between the clients and the server. You basically have two major options: HTTP and web services (in that case, consider using either JAX-WS or JAX-RS) or RMI-IIOP and EJBs (in that case, you'll have to use a Java EE compliant server like GlassFish).
I have looked for Tomcat, Jetty and Glassfish but it seems that they are only used for web application.
Not really. As I said, they can also be used for web services oriented applications. And GlassFish can be used for EJBs applications.
Which package archive should i use (jar, war)
The packaging will depend on the type of application you'll write, it's not something that you choose upfront, it's just a consequence. EJBs are packaged in an EJB JAR and typically deployed inside an EAR; Servlet based web services are deployed inside a WAR.
You really need to think about what technology to use first (with the current level of detail, I can't provide more guidance).
Do you even need an application server? There's nothing stopping you from adding the necessary network bindings and deploying it on its own.
Of the servers you mention, you've got 2 different categories: servlet containers and full-stack Java EE servers
Tomcat and Jetty are servlet containers. That doesn't mean that you can only do web stuff with them and you could manually add the required libraries to get a full Java EE server.
Glassfish is a full-stack Java EE server and can be compared with JBoss (both are open source) or the commercial rivals Weblogic and Websphere.
Sometimes this question is simple as the environment you are working in mandates a particular flavour of app server. You should check this first.
If you're not forced to use an app server, I'd ask why you think you need to use an app server?
I don't see why you would want to use tomcat, glassfish or jetty for a command line program.
If it's command-line based, and you want it to run server-side, you could write a little program that allows users to, for instance, telnet to your server, which in turn starts the CLI-application in question, and relays input / output to the client.
You may also want to look into Java Webstart, which makes deployment of new versions a breeze.
Actually we can't answer with so few elements.
- What are you planning to do
- With what technologies
- Where are you planning to host your application (have you got budget?)
- In which language are written the clients (even the future ones)?
- Could clients be on mobile phones (add some technlogy constraints...)
....
It would also be great to know what kind of request the clients will do, and what kind of response the server will provide...
Actually with what you tell us, all those application servers can do what you want...
I have looked for Tomcat, Jetty and
Glassfish but it seems that they are
only used for web application
You could even make a webapplication (servlet) and on the clientside use a httpclient to call that servlet... there are so many options :)
vive Paris!
I've a small doubt in my mind; could anyone please clarify me is the Tomcat web server or Web container?
It's both a web server (supports HTTP protocol) and a web container (supports JSP/Servlet API, also called "servlet container" at times).
As mentioned above, Tomcat is both a web server and a web container, but it's not really meant to function as a high performance web server, nor does it include some features typical of a web server. Tomcat is meant to be used in conjunction with the Apache web server, where Apache manages static pages, caching, redirection, etc. and Tomcat handles the container (web application) functions. You'll often hear the phrase "Apache Tomcat" together, which is both a proper attribution of the Tomcat project (as part of the Apache Foundation), but also appropriate as a label, as they're usually used together as a package.
If you don't have an high performance server requirements and/or want to embed a relatively simple web server with container functionality, Tomcat is fine for that (and probably the easiest embedded web container to work with, comparable with Jetty). Interestingly, the Catalina class used as the main Tomcat engine is actually a subclass of the Embedded class that can be used in a standalone web application.
A web server is any program that accepts incoming HTTP connections.