I want to convert a Java/Dynamic web project to a Maven project. I use Eclipse IDE to develop Java applications.
One of the straight forward options available to me is to use 'Convert to Maven project' in Eclipse. But there are situations where I cannot use that option since the Maven plugin doesn't work in some networks like my Work environment.
So I want to know a Maven command (on Command Line) that would help me convert my Eclipse-built Java Web App to a Maven project.
Thank you in advance, Happy learning.
The Eclipse feature "Convert to Maven Project" works on projects that already have an appropriate POM. A project that was initially created by Eclipse doesn't have that POM.
So what you must do, is simply create a POM with packaging type WAR, then put it into the root of the project.
You also have to take care of the source directories. The Maven standard way is to have all sources under these four directories:
src/main/java
src/main/resources
src/test/java
src/test/resources
Eclipse simply stores everything under src. So you either change your file and directory structure, or you change the appropriate <build> parameters in the POM. I suggest the former.
The "Convert to Maven Project" feature does more than adding the Maven nature to the Eclipse build settings. It also creates and configures the Eclipse project meta files (the files .project and .classpath and the folder .settings). Therefore I suggest to delete them first in your project directory, so Eclipse can start on a clean project.
Afterwards you simply can convert your project with the above mentioned feature. It should create the meta files, and - as it is a web project (packaging type WAR) - it also should add the appropriate natures that let Eclipse show the project as a web project.
Related
I have a Java project that depends on a 3-rd party component. This component is available both as a jar and as a Maven/Ant project. One option for me is to simply add the jar as a library. However, I prefer to add the source code into my project since I may need to slightly modify their source code to better suit my needs.
What's the right way to do it in Eclipse?
My main project has a simple structure: src/ and lib/. The external component also has a standard structure: src/, test/, build/, target/, pom.xml, build.xml. So do I need to copy piece by piece (like contents of one src/ into the other src/), in which case what goes where? Or do I somehow copy it all at once? Or smth else?
The best way would be if you use maven on your projet for dependency management. This way, if you have the other projects open in eclipse, your project will resolve them as local projects, but if you don't, maven will try to fetch the jars from the configured nexus repository.
This way, you avoid having to manually configure your Eclipse projects. Maven will be able to configure your project anywhere you want to build it, not having to manually configure dependency resolution.
Import both the projects into eclipse. Add the reference of 3pp jar project to your project as a reference by clicking on Add on build path option. While delivering it as output there will be a dependency to the 3pp jar project. So either deliver it as separate jar and add it to classpath while executing your project else you have to copy the entire source files into your project and deliver it test complete jar.
Making a jar will be handled by eclipse itself.
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
I accidentally converted my project to Maven by going to Configure > Convert to Maven Project. Now I want to undo this. I read that I need to right click Maven > Disable Maven Nature and that worked fine. However I want to totally remove Maven, so I deleted the pom.xml and the target folder. When I try to run my code now, I get the error:
Error: Could not find or load main class
So what am I missing? How do I revert from a Maven project to a non-Maven project?
When you convert a Java project to a Maven project in Eclipse, the Maven Integration for Eclipse (m2eclipse) configures the Java incremental compiler to put the compiled class files in the same location as Maven would put them, i.e. target/classes.
So when you remove the Maven nature and delete the target folder, you now also have deleted the compiled class files and your project can no longer run. AFAIK, the incremental compiler doesn't detect when you remove its output files, so you need to trigger a rebuild by cleaning the project (Project > Clean...)
This will fix the problem that you can not launch your project, but may re-create a target folder. If you also want this to be "fixed", you can switch back to some other folder name for the binaries, e.g. bin, in the project's Java Build Path configuration on the Source tab.
Is it basically a Maven project, i.e., do you have and maintain it through a pom.xml? Then my suggestion is to delete the project in Eclipse but keep the files on the disk (i.e., it removes it from the workspace). Then, run a simple mvn eclipse:clean eclipse:eclipse which creates a simple Java project without the Maven nature based on the POM (so the libraries are linked and the source/output directories are set up correctly - this may solve your ClassNotFoundError).
If it's a simple Java project, I would advise deleting it from the workspace, removing the .classpath and .project files and importing it again with the Create a Java project with existing sources wizard.
Either way, make a backup of your project before you start doing anything :-)
I am using Eclipse Kepler for Java. Normally you can add internal/external .jars to a Java project in the build path located in the properties. Why, when I clone a git repo and import it into my projects, do I lose that ability? I don't understand. I kinda need to do that.
This is probably because the .gitignore has been configured to ignore .jar
Open the .gitignore file and remove the line *.jar, you should be able to add it.
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As an aside - usually, for Java projects .jar files are not committed to repository (as they are large & it can slow down repository cloning), instead maven or gradle is used to configure dependencies. Example - http://www.mkyong.com/maven/how-to-create-a-java-project-with-maven/
Then when you want to work with eclipse just run mvn eclipse:eclipse to generate the necessary files. .gitgnore is usually set up to ignore *.class, *.jar, .project, .settings, .classpath
I found that if you open the run configurations and go to the Classpath tab that you can add internal/external .jars. The run configuration can be accessed by clicking Run > Run configurations. I added my .jar to the user entries. The bootstrap entry caused a null pointer.
When a project relies on libraries/modules, it's best to use a build tool for dependency management. JVM ecosystem is dominated with three build tools: Gradle, Maven and Ant.
How it works:
In a build script we declare dependencies of the project. This tells the build tool where to retrieve libraries/modules our project depends on. Dependencies are resolved at runtime; downloaded from a remote repository, retrieved from a local directory or if required another project to be built in a multi-project setting.
I've inherited a web project (Servlets) which is currently build inside eclipse.
I want to add maven around it. But the project's source directory is not following the maven convention. Instead of being inside src/main/java, it's src/package/name/...
I don't want to change anything right now because they are working at full speed towards a milestone. Can I configure maven to accept src/ as the java source directory ? Thanks
Just add this to your pom in the build section.
<sourceDirectory>${basedir}/src</sourceDirectory>
Here's the relevant section of the POM doc on configuring the directories.