I have a simple webapp in an mavenized Eclipse project.
My pom.xml contains some lines that add Google's appengine-maven-plugin to the build plugins.
When I run mvn appengine:devserver I eventually get an error telling me that my class could not be loaded:
[INFO] WARNING: Error starting handlers
[INFO] java.lang.ClassFormatError: Incompatible magic value 4022320623 in class file com/teamlazerbeez/http/di/StartupListener
That number is EFBFBDEF in hexadecimal notation, something that is clearly not CAFEBABE, the byte sequence Java class files should start with.
I only found this and this on the subject matter, which leads me to believe that the encoding went wrong during either writing or reading the class file.
Is this the problem? How do I force maven to read/write classes with e.g. UTF-8 encoding?
And what is a good encoding?
My java files are all encoded the same way: Eclipse says ISO-8859-1, Notepad++ says ANSI.
PS: I'm on a windows machine.
As Joakim Erdfeld's answer suggests, one of the plugins is fiddling with the build.
The culprit is the maven-war-plugin v2.3, but only in the following situation:
Having the GAE nature enabled on the mavenized Ecipse project (where the appengine-maven-plugin v1.7.5 is listed in the pom.xml) will break running mvn appengine:devserver iff the following conditions apply:
'default output folder' (in the Eclipse project's 'Build Path' settings) is set to src/main/webapp/WEB-INF/classes/ (required for the GAE Eclipse plugin to work)
The GAE plugin decided to put GAE-jars in src/main/webapp/WEB-INF/lib/, even though these jars are already in the classpath.
In conclusion, the maven-war-plugin improperly copies .class and .jar files from your WEB-INF/ to your resulting .war file. Somewhere in the process, it mis-encodes these files.
Check your src/main/webapp/WEB-INF folder, it should not contain a classes folder.
If it does, it means you probably misconfigured your eclipse project.
One case we encountered is that the developer imports a maven project and runs the project "as a web application". The first time he does this, Eclipse asks him where the webapp folder is. If you answer src/main/webapp then Eclipse will put its classes there, and it will get messed up by maven after.
To solve this, delete the project from Eclipse and remove the src/main/webapp/WEB-INF/classes folder, then re-import the project.
And when Eclipse asks where the webapp folder is, it is in target/yourproject-yourversion.
Something in your maven build is messing with the class files after the compile and before the package phases.
Start by commenting out all of your <plugins> and then adding them back 1 at a time till the build breaks again.
Be sure you run > mvn help:effective-pom to check on what your pom looks like when it has been fully resolved to parent poms and whatnot.
(Experimental) You can possibly even get the build itself to tell you if the classes are bad by simply using the project-info-reports command line for the dependencies report.
> mvn clean org.apache.maven.plugins:maven-project-info-reports-plugin:2.6:dependencies
I found this question which also mentioned the invalid magic number EFBFBDEF. It also seems to suggest that you set the maven encodings properly. Use the following property:
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
But I think that this only helps if you get an encoding warning during the maven build process.
Related
I had a GWT app, and I wanted to automate its build and deploy system, since I do it manually. But I did not find a way how to build the app from command line, so it can than be automated. I had to click the Google button, then compile GWT project and then click Compile.
I found out that it is possible to create a GWT maven project and that it should then be possible to compile my project from commandline with mvn gwt:compile.
So I created a new project using this plugin. Copied my sources from the old project to this new one.
Now the structure is like this:
/src
---/main
------/java -> here are all my sources including my Project.gwt.xml file.
------/webapp
---/test
pom.xml
Now I have 2 problems.
1. I thought that I add dependencies to the pom.xml, and then when I build the app, it will create the jars and I can use those libraries in my GWT app. I guess 'mvn clean install' should do this, but so far I'm getting compile errors.
2. I did not get mvn clean install to work, so I added all the jars manually again... And then yes! I was able to build the app using the plugin GWT button! So I was thinking that now I can use 'mvn gwt:compile', but it fails with:
Unable to find: "com/company/project/Project.gwt.xml" on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?
EDIT:
So I fixed my <moduleName> element in pom.xml, so now it finds the Project.gwt.xml. I'm trying to run:
mvn clean install gwt:compile
But I am getting compile errors. I think, it tries to build my project without the actual dependecies because it tells few classes don't exist, but those classes are part of an external library. (specifically this one). But I have it in the dependencies, so I don't know what more to do.
<dependency>
<groupId>com.github.tdesjardins</groupId>
<artifactId>gwt-ol3</artifactId>
<version>3.0.0</version>
</dependency>
Also in eclipse I had to manually add the jars to my project, so that was why it worked there and not in the command line. So I would also like to ask how to tell eclipse to get those jars and include them to the project, because otherwise eclipse is missing those dependencies and displays many errors.
First I had a problem with <moduleName> in my pom.xml was missing com.company.project prefix before the actual module name.
Then I had errors in my Java files, which was caused by RELEASE version of GWT-OpenLayers 3 library missing some of the features that I previously used by building the JAR from the GitHub repository.
I have multi module maven project, that is build with gwt as a main web framework. Here is github repo.
Everythink works as it should as I supose. I haven't got anything wrong.
Unfortunatelly the problems occur when I try to import this project into eclipse (as maven project). I can not compile this project (using RMB on project in Package Explorer -> Google -> GWT Compile).
I am getting an error:
Loading inherited module 'src.main.resources.pl.derp.parent'
Loading inherited module 'pl.derp.shared'
[ERROR] Unable to find 'pl/derp/shared.gwt.xml' on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?
When I tried to RMB on Project name in Package Explorer -> Run -> Run as Web application (GWT Super Dev Mode)
I've got:
Working directory does not exist: /home/danielo/eclipseGwt/gwt_2.7.0_maven_eclipse/web/src/main/webapp
I've added modules to build path.
I've followed this instruction
I think, that I've done everything to make it work, but still can make it work.
I think the problem is in packages name, and the way they are treated by maven and eclipse. They are treated in diferent ways.
Maven easily find every class (f.e.: package pl.derp.web;) needed and compile. The eclipse is trying to find them by f.e.: src.main.java.pl.derp.web but can't found it.
Really I don't know how to resolve this issue?
I am not sure witch package name patter is better (src.main.java.pl.derp.server or pl.derp.server)- for me the shorter is better.
To run this project in maven (it is well described here):
mvn clean install
mvn tomcat7:run-war-only
and in second shell:
mvn gwt:run -pl web
And in Eclipse I think I am running built in Jetty server
Please give me some help.
You apparently have a single Eclipse project, with server, shared, and web declared as source directories. When using M2Eclipse, you should have 3 projects, each with their src/{main,test}/{java,resources} declared as source directories. At a minimum, without M2Eclipse, the source directories must be the src/{main,test}/{java,resources}, whether you have 1 or 3 projects.
This is why Eclipse looks for src.main.java.pl.derp.server instead of pl.derp.server, and why GWT fails too (classpath is similarly wrong).
I have a Java project that is ready to ship, but i have stumbled at the last hurdle. The program runs fine in the IDE, but after i run mvn clean install and the target jar is created successfully, the application fails both on the command line AND in the IDE. I can get it to run again in the IDE by doing a rebuild from within the IDE.
Has anyone else experienced something similar?
The error after the mvn clean install is
2014-08-08_10:38:20.328 INFO coza.modh.fxplatform.Controller - Application start
2014-08-08_10:38:20.344 INFO c.m.f.c.p.DataSourceFactory - Connecting to Database.
2014-08-08_10:38:20.499 INFO coza.modh.fxplatform.Controller - Model created
Exception in thread "main" java.lang.NullPointerException
at coza.modh.fxplatform.view.MainView.<init>(MainView.java:46)
at coza.modh.fxplatform.Controller.startup(Controller.java:40)
at coza.modh.fxplatform.Application.main(Application.java:7)
The line it fails on looks like this:
setContentPane(contentPane);
If i rebuild from within the IDE then the variable is not null when it gets here, but after the mvn command the variable is null when it gets to this point.
EDIT: Someone pointed out that it might be related to the fact that i used the intelliJ GUI designer tools and that Maven might not gel with it. Possibility?
I had a similar problem today. To solve the issue -
Firstly, add the following to the pom.xml
<dependency>
<groupId>com.intellij</groupId>
<artifactId>forms_rt</artifactId>
<version>5.0</version>
</dependency>
Secondly, as you stated, use the correct maven plugin to create the build.
See this for step by step instruction.
Unlikely that contentPane is null, but check. Do a clean build anyway. Maybe the line number is not entirely correct.
Normally the problem are resources, like an application icon.
They are not File but zipped inside the jar.
So paths like /src/main/resources/... will not do.
Neiter using a backslash \, and
furthermore the file paths are case sensitive.
This can be caused by different library versions, do you have changed the build path in Eclipse? (Project->Properties->Build Path -> Libraries). There should only be "JRE System Library". If there is more, then it is possible that it is be loaded instead of one of your Maven dependencies. You using "mvn clean install" means it is compiled against the Maven dependencies and thus it runs differently.
Install Maven on the system(not having IDE) before running the code
ensure you've got system property M2_HOME set to your Maven installation location and also Maven bin folder added to PATH
go to the directory,containing pom.xml of your project and type "mvn install" plus Enter to build your project
if it's for example simple project,packaged as JAR,you can run it then by typing something like this in the console:
$ java -cp target/simple-1.0-SNAPSHOT.jar org.yourcompany.projectNam.App
and Enter
I guess I haven't really had to do this much before because I am running into a strange issue. I am trying to generate a JAR from an existing Java project and then and putting it into a Spring Maven project. I'm sure I'm including it correctly, I have done this many times before with 3rd party JARs that I get (even though its a Maven project I have included some obscure JARs in it and put on buildpath, etc), with my JAR within Eclipse it is showing up fine as if its included, I have a test class that is importing a class from the JAR, instantiating it, etc and its not showing any errors (imports are fine in the IDE, etc), however when I go to do a Maven install I get:
[ERROR] /media/src/main/java/org/jadefalcon/automation/DataSetup/test.java:[11,15] package org.test does not exist
[ERROR] /media/src/main/java/org/jadefalcon/automation/DataSetup/test.java:[21,2] cannot find symbol
I have tried doing a Maven clean but still the same problem, the JAR class I am testing with is this: (was trying a more complex one but then tried this to troubleshoot the issue)
package org.test;
public class something {
public String main () {
return "it is definitely working fine";
}
}
Here is the JAR I generated (with sources visible):
https://docs.google.com/leaf?id=0BzB_xvrbRpbYODQyMjEzOWEtOTdjNS00YjM3LTlkZGUtNjY5NmIwN2RiNTRj&hl=en
I would appreciate any advice as I am rather perplexed and frustrated by this. Thanks
You can include a 'regular' jar in your maven project -just as you described- though it's not a best practice mainly because then you not even lose the functionality of Maven for that jar, but also the whole point of Maven dependency management: you will have to include that jar with your source to make it build.
You can of course also create a Maven artifact for that jar, build it with Maven, install it with Maven and use it as a normal Maven dependency.
You also can create a parent .pom and have your dependency project as a module in it and also your real application (or also your real app can be your parent). See further here.
Since this caused me quite a bit of grief, I figure I should post the solution I found. Apparently you aren't supposed to just include a regular lib JAR in a maven project (although I swear I have done it before and it worked), I found this way to include a local JAR that isn't form a repository from this post:
Can I add jars to maven 2 build classpath without installing them?
I did this and its doing the maven install properly (where version and artifactID are just made up value)
<dependency>
<groupId>org.test</groupId>
<artifactId>test</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${basedir}/lib/testjar.jar</systemPath>
</dependency>
I'm working on a swing project, using maven2 (from command-line) and eclipse (without maven integration). So, I generate the eclipse project through maven eclipse plugin (mvn eclipse:eclipse), import it inside eclipse, and do all my work.
My problem is: when I run my app in eclipse (as a Java Application), I can't find none of the resources that are in my src directory. Digging for information on my problem, I get into this answer from another question. So, I compared the output from the following instructions:
MyClass.class.getResource("/").getPath();
MyClass.class.getProtectionDomain().getCodeSource().getLocation().toString();
Those gave me the following outputs, respectively:
${workspace_loc}/${my_project}/target/test-classes/
file:/${workspace_loc}/${my_project}/target/classes/
Checking the above locations, I could see that the former is empty, while the other one contained all my compiled classes and resources. So, I came to the conclusion that the classloader is looking for my resources in the wrong place. So, I think I have three questions:
Is my understanding correct?
If so, how it does to find the classes it is loading?
How do I solve this?
UPDATE: I've changed my code, so instead of invoking MyClass.class.getResource(...) or MyClass.class.getResourceAsStream(...), I'm now using ClassLoader.getSystemResource(...) and ClassLoader.getSystemResourceAsStream(...). In this way, everything is working fine in eclipse. I just don't know exactly why. Any hint on this?
Two possibles cases for me :
You are using eclipse to compile your project. Then eclipse is configured to exclude (or not include) resources in the src folder. You can set it in Project/Properties/Java Build Path/Source. Then you expend your src folder, and ensure you have something like "Included All", "Excluded None".
You run your maven application using maven to compile and not eclipse, even though you are using eclipse as your IDE. Then by default maven will not copy resources from the source folder to the output folder... Because it is not the standard maven way of doing things. Thus the resource are missing from the classpath and you don't find them. Just change your maven configuration to also include resources from your source folder.
I think you have to add src/main/resources to the build path. This is done in Project Properties > Build Path > Source. Here is how the standard maven project looks:
In future when using Eclipse I suggest to use m2eclipse plugin and create project using it. This will automatically make sure that all these folders are in the build path.
Try this:
Run configurations... -> Classpath -> User Entries -> Advanced... -> Add Folders
Can you try loading the resources using below?
this.getClass().getClassLoader().getResourceAsStream(propertyFileName)
This might be useful information
Eclipse Maven plugin has its own Classpath Container that conflicts with generated class paths when enabled.
What I would suggest is stop using eclipse:eclipse (sorry - harsh I know). I used it for about 8 months, cant believe it took me that long, and used M2Eclipse. M2Eclipse is an eclipse plugin in which you do the following.
Enable Dependency Management.
Update Project Configuration
(In Eclipse) Project -> Build Project
(In Eclipse) Run Application
It may not seem it, but its a much easier and less frustrating way of doing it.
Before, with eclipse:eclipse. You would have to run it then hit refresh and hope that everything is configured - if you have a multi-module pom things can really go wrong.
For me the Files within the WEB-INF were not getting included. Hence I added them to Buildpath (Project -> Build Path -> Configure Build Path -> Add folder (project/src/main/webapp). This resolved the issue.