Develop Reference

Is it possible automatically compile depended project into jar in Eclipse?

For example I have a regular Java project and multiple EAR projects JSF + EJB inside EAR. Each EAR project has as a dependency, my Java project, for example it might be a library of composite JSF components.
Is it possible to define that when I exporting an EAR project it will compile depended Java project into jar and put it as a library inside EAR\libs?
Same thing regarding committing project via RTC, now I need manually build jar and add it to my EAR project, is it possible to do it automatically?

RTC wouldn't provide any additional compilation feature compared to the platform (Eclipse) it is installed on.
It does provide however RTC Builds, and you could use that task scheduler to, on demand, trigger the compilation of the Java project and its import into the ear/libs.
That supposes first that you can do those tasks in a script (using any scripting technique you want: ant, maven shell, bash, anything).
Then you can define a build definition using that script.

Eclipse build automatically to do maven build?

I have my main web application(has its own POM) that is dependent on module A((has its own POM).
When i make a build using mvn install on web application, it dependent modules
are also built in to jar file and ultimately included under WEB-INF/lib folder of main web app.
But that does not happen in when i make build using eclipse kepler (containing both maven projects i.e main web app and its dependent module A).
When building with eclipse, it just put the modified classes under moduleA/target/classes/ folder but does not make any updated jar file and put it
under WEB-INF/lib folder of main web app.
Is there a setting where i can configure eclipse building the project same way as maven does (which will really save lot of time and help in hot deployment) ?.
It used to work in one of my projects looks like some configuration is required for this.
looks like m2e connector(i have SonarQube) needs some configuration to make eclipse build in the same fashion as maven build
When i do the project > right click > mvn install , i am able to make jar file.
But what i want is eclipse build automatically option do
the build for project/module wherever modification is done , construct the jar and include it in parent WEB-INF/lib folder if it is dependent module ?

Assuming you're using the Java EE flavour of Eclipse, you can easily deploy Maven based web applications to a local server (like Tomcat, Wildfly...) from the server view.
m2e-wtp, included in recent Eclipse Java EE distros, takes care of configuring all Eclipse settings based on your project pom.xml configuration and dependencies.
See this screencast to see how simple it is : https://www.youtube.com/watch?v=TksoKkSP208
For the record, deployment/publishing is performed by each server adapter differently. They're responsible for publishing the proper jars under the WEB-INF/lib folder of the deployed application. Dependent jar projects are automatically zipped and deployed to WEB-INF/lib without user interaction

Adding plain Java project as a classpath to an eclipse plugin

I have a plain Java project (not a plugin project) which I want to add to a classpath of a eclipse plugin which I am developing. But in web projects I can add that project as a build path and it works fine. But I tried same thing in eclipse plugin, I am able to compile successfully, but at run time I am getting java.lang.ClassNotFoundException.
I know OSGi quite well and I know how to add OSGi into an classpath (using export-packages) but what I want is to add Standard, non-osgi project into an classpath, so that I wont' get runtime errors. Is there anyway I can achieve this?
I can export project as a jar file or make it as a plugin project and it would work fine. But that's not my option currently because, still that API is in pre-alpha stage, and there would be lot of changes going on. So I am trying to avoid pain of exporting it as jar file everytime. Is there any option for me other than this?

I have a similar situation: I want non-OSGi Maven dependencies integrated into the classpath of my plugin. I succeeded with a roundabout solution, which I think is the best I could get.
I have a build step outside of Eclipse where I copy the class files of the dependency into the plugin's lib folder. The lib folder is specified in MANIFEST.MF as an entry in Bundle-ClassPath and (here comes the hack) as a source folder in build.properties. That was the only way to make the plugin work both when launched from within Eclipse and when exported.

Java classpath for dynamic web project

Hi all i have very rare problem which needs to be solved.
Problem/issue:
I have a dynamic web project which is already built and i have war file of that project.
I need to apply some customizations on top of the war file given to me.
Using maven or ant am able to compile the custom code written by me and able to add produced class files to the war file.
But the this is happening for final war file build.
when i want to test my code in eclipse. the war file build and deployed in jboss plugin contains only the class files produced out of java files written by me..........
Please help me how can i modify the .classpath file of my project so that a jboss publish can build a war file using the dependent war file which can run on eclipse-jboss to test my custom code....
Advance Thanks.....

Not a rare problem.
What you need to combine two web applications (wars) together. You have your customization war on which you need to overlay the existing web application.
It looks like you have already solved it from build perspective and looking for Eclipse support. To my knowledge, Eclipse lacks support for this. You probably need to manually do the necessary configuration to make this happen.

It looks strange to me to have two WAR files.
Perhaps you have to consider to package your customizations in a JAR and inserting that jar in the original WAR file.
Otherwise, another solution, and what I do often with open-source project to customize is to have three projects in your workspace.
PRJ-src (with your original sources/JAR/WAR)
PRJ-custom (which depends of the previous one); This project contains only the new classes or custom spring xml files (with injection of my own classes)
PRJ (the merge of the two previous projects)
I create an Ant task in the 3rd project which takes the 1st project (PRJ-src) and merge with the 2nd project (PRJ-custom). This is possible to do so with Maven as well.
Then this is the only project I deploy in my app server (tomcat / jboss).

Java Web Project referencing another Java project

I have a Java Project, for which I'm now creating a Web interface, using a Dynamic Web Project from Eclipse. The Web project consists of a single servlet and two JSP's. Something like this:
/JavaApplication
/src
/lib
/resources
/WebApplication
/src
/Servlet.java
/WebContent
/WEB-INF
index.jsp
other.jsp
Now, I need to reference JavaApplication from WebApplication, in order to use its classes to process web requests. What's the best way to accomplish this ? My idea is to create a .jar of the JavaApplication, containing all the .class files, /resources, and /libs. In this way, I could include the .jar in the web application, and I could have a single .war file that contained the entire application.
What do you think? How is this problem typically solved ?
Note: I don't want to convert the Java Project into a Web project.

In Eclipse project properties, add the project to the Java EE Module Dependencies (Eclipse 3.5 or older)
or Deployment Assembly (Eclipse 3.6 or newer) entry in the project properties.
This way Eclipse will take care about doing the right thing to create a WAR out of this all (it will end in /WEB-INF/lib). No other configuration is necessary, even not some fiddling in Build Path.

Under Eclipse, you can declare Project References for a given project, the web application in your case. To do so, right click on your web application project, then go for Properties > Project References and select the JavaApplication project. This should allow you to call code from the JavaApplication project from the WebApplication without having to build a WAR. This is a solution for development.
For standard deployment (outside the IDE), you should indeed create a standard WAR. To do so, you'll have to package your JavaApplication as a JAR including the .class files and the files under /resources but not the libraries it depends on (JARs under /lib). These dependencies will actually end up in the WEB-INF/lib directory of the WAR, beside the JAR of your JavaApplication. These steps are typically automated with tools like Ant or Maven.

Connecting java app to web app for development :
right click on web project :
properties>project references> add the java project you want to refer
Now in properties tab of web project go to
properties>deployment assembly> add the project manually and run the app

Consider moving up to EAR level, if your web container supports that.
The tricky part with shared code is where should the common code be put. A copy pr web application? A copy in the web container? Overdoing the "share these classes" might end up in class loader problems.
If you are creating two separate web applications refactor common java code into a separate Eclipse project and refer to it from both WAR projects.
EDIT: Apparently I have misread the problem description, and thought you asked about an existing and a new web application sharing code.
If you have an Eclipse project with your application, and another with your web frontend, then you can let your application export the necessary resources which the "Export WAR" in Eclipse Java EE can wrap up in a jar file and put in WEB-INF/lib for you. You need to say this explicitly with a checkmark in Properties -> Java EE Module Dependencies for your web project. Expect you have to experiment a bit - this took me a while to learn.

Typically you would create an API interface using remote service beans from the Java application that expose the methods that you want to invoke in the web application. You would include a proxy of the API interface with your web application that calls the remote service bean in the Java application. Remember that you will need to register the remote bean in the web.xml file.