I`m developing client that uses library Overthere 2.3.1. With local machine client works perfectly. But when I try to call same code included to EJB 3.0, I've got exception that not all required classes have been loaded.
I`ve looked over the source and found that the class contains Protocol annotation scanner (https://github.com/hierynomus/scannit) with hardcoded class name:
Scannit scannit = new Scannit(Configuration.config()
.scan("com.xebialabs")
.with(new AbstractScanner[] { new TypeAnnotationScanner() }));
The command
Thread.currentThread().getContextClassLoader().getResources("com/xebialabs")
returns null.
Looks like EJB runs in a separate classloader which does not have access to all the jars.
The EJB is packed to EAR with following structure:
EAR
--META-INF
----sda-dd.xml
----SAP_MANIFEST.MF
----MANIFEST.MF
----application-j2ee-engine.xml
--ejb.jar
--extlibs.jars
The MANIFEST.MF file don`t contain any referenses to external libs in CLASS-PATH. The EAR project is deployed to Application server successfully.
The EJB.jar also contains META-INF/MANIFEST.MF with value "Class-Path: ." by default.
I`ve already tried playing around with CLASS-PATH in manifest files, but have no luck.
Could anyone help me, how to build project with all external libs to be loaded while EJB runs? What have I missed with resources and classloaders?
I have a Spring Configuration java file in my project (i.e. with #Configuration annotation). Now I'm creating a bean of SpringLiquibase in this class. The main file of changelogs i.e. db.changelog.xml file is in resources folder. So directly it's accessible from resources folder if I use springLiquibaseObj.setChangeLog("classpath:db.changelog.xml"); method. But when I try to access other xml files from db.changelog.xml file with <include file="src/main/config/db/db.changelog-main.xml" /> I get error that folder and file is not found.
Here, I want to keep db.changelog.xml file in resources folder and all other new changelog files in config folder which should be at same level as resources. The reason for this is, in resources folder, packages are there so folder structure config/1.0.0 is considered as config/1/0/0 which I don't want.
Is there any way to achieve this structure (shown below) with the current set up in my project?
config
1.0.0
db.changelog.201412120101.xml
1.1.0
2.0.0
resources
db.changelog.xml
or
config
1.0.0
db.changelog.201412120101.xml
1.1.0
2.0.0
db.changelog.xml
resources
I found the solution for this. Before this, I had copied the folder src/main/config into src/main/resouces in netbeans so it took that folder as package. So the folder name - config/db/1.0.0 got changed to config/db/1/0/0, but when I created new folder in resources folder, it worked and all the files in folder 1.0.0 are accessible correctly. Now, my folder structure is like this:
resources
config
db
1.0.0
db.changelog.201412120101.xml
1.1.0
2.0.0
db.changelog.xml
I can access db.changelog.xml file from my Spring class as,springLiquibaseObj.setChangeLog("classpath:db.changelog.xml"); and other changelog files from db.changelog.xml file as, <include file="classpath:config/db/1.0.0/db.changelog-201412120101.xml" relativeToChangelogFile="false" />.
Liquibase uses the application classpath, so as long as config is in your classpath you should be able to load them as well.
They would have a path relative to config, so something like "src="1.0.0/db.changelog.201312120101.xml" in your example.
If config isn't in the classpath, you can use the relativeToChangeLog="true" attribute with a src="../../config/1.0.0/db.changelog.201412120101.xml" but having config directly accessible by liquibase is the cleaner option.
I have a Maven project that I'm trying to package as both a war and a jar. As part of my application / servlet initialisation (depending on whether I'm running the jar or the war), I need to read a file called server.ini. I've put the file in src/main/resources/server.ini and am trying to load it like so:
System.class.getResourceAsStream("server.ini");
However, this always results in null. What am I doing wrong?
The server.ini file should be in the root of a resources directory.
By placing it in the webapp you're making the file available via http, but you need it accessible on the classpath, which means that you should place it in the resources directory.
There's a good chance web.xml or context.xml is better suited to what you're trying to do, but...
Try putting server.ini in WEB-INF/classes, or do something like this.
The issue was that I was using the System classloader with an unqualified path, so it was expecting to find my server.ini in the java.lang package.
Since my file is in src/main/resources, I should just use the classloader of my current class, with an absolute path:
getClass().getResourceAsStream("/server.ini")
This works in both the war and the jar.
The "Preferred way of loading resources in Java" question has a great explanation of resource loading.
I am trying to deploy my web application on jboss-6.0.0Final, which is currently deployed on apache tomcat.
I have two jars one that contains same package which is org.apache.axis. I am putting one jar in <Jboss-home>/server/default/lib & another jar in <my-app-war>WEB-INF/lib.
It is required to put both jars in the class path. No way to remove one of the jar. So I need to keep both jars. & It is giving me following error
java.lang.ClassCastException: org.apache.axis.attachments.AttachmentsImpl cannot be cast to org.apache.axis.attachments.Attachments
at org.apache.axis.AxisFault.makeFault(AxisFault.java:101)
at org.apache.axis.client.Call.invoke(Call.java:1828)
I think it is due to conflict of same classes in two different jars.
Now, I want to know the way by which I can force jboss to load classes of this particular package from axis.jar exist in /WEB-INF/lib.
How can I do that?
This helped me:
http://www.mastertheboss.com/jboss-configuration/solving-jboss-5-classloading-issues
Explode your war,
In your Exploded WAR web-inf directory add this xml file: jboss-classloading.xml
with content:
(domain is your war name)
<classloading xmlns="urn:jboss:classloading:1.0"
name="mywar.war"
domain="mywar_domain" <!-- (domain is your war name) -->
parent-domain="Ignored"
export-all="NON_EMPTY"
import-all="true">
</classloading>
I'll share quite simple and straight forward process which I had followed when I came across same situation.
1> Create a jboss-web.xml file.
<class-loading java2classloadingcompliance="false">
<loader-repository>
com.rts:archive=DTH_PROD.war
<loader-repository-config>
java2ParentDelegation=false
</loader-repository-config>
</loader-repository>
</class-loading>
</jboss-web>
Points:,
Begin the xml with tag which is not visible in the code I'm posting
Check 3rd line of above code,
com.rts - This is your package name.
DTH_PROD.war - Name of bundle you wish to keep
2> Now place this xml file into WEB-INF directory of your project and voilla!!
Further more you may wish to refer this article for detailed info. Also comment below if you face any difficulty solving this.
In Java, you often see a META-INF folder containing some meta files. What is the purpose of this folder and what can I put there?
From the official JAR File Specification (link goes to the Java 7 version, but the text hasn't changed since at least v1.3):
The META-INF directory
The following files/directories in the META-INF directory are recognized and interpreted by the Java 2 Platform to configure applications, extensions, class loaders and services:
MANIFEST.MF
The manifest file that is used to define extension and package related data.
INDEX.LIST
This file is generated by the new "-i" option of the jar tool, which contains location information for packages defined in an application or extension. It is part of the JarIndex implementation and used by class loaders to speed up their class loading process.
x.SF
The signature file for the JAR file. 'x' stands for the base file name.
x.DSA
The signature block file associated with the signature file with the same base file name. This file stores the digital signature of the corresponding signature file.
services/
This directory stores all the service provider configuration files.
New since Java 9 implementing JEP 238 are multi-release JARs. One will see a sub folder versions. This is a feature which allows to package classes which are meant for different Java version in one jar.
Generally speaking, you should not put anything into META-INF yourself. Instead, you should rely upon whatever you use to package up your JAR. This is one of the areas where I think Ant really excels: specifying JAR file manifest attributes. It's very easy to say something like:
<jar ...>
<manifest>
<attribute name="Main-Class" value="MyApplication"/>
</manifest>
</jar>
At least, I think that's easy... :-)
The point is that META-INF should be considered an internal Java meta directory. Don't mess with it! Any files you want to include with your JAR should be placed in some other sub-directory or at the root of the JAR itself.
I've noticed that some Java libraries have started using META-INF as a directory in which to include configuration files that should be packaged and included in the CLASSPATH along with JARs. For example, Spring allows you to import XML Files that are on the classpath using:
<import resource="classpath:/META-INF/cxf/cxf.xml" />
<import resource="classpath:/META-INF/cxf/cxf-extensions-*.xml" />
In this example, I'm quoting straight out of the Apache CXF User Guide. On a project I worked on in which we had to allow multiple levels of configuration via Spring, we followed this convention and put our configuration files in META-INF.
When I reflect on this decision, I don't know what exactly would be wrong with simply including the configuration files in a specific Java package, rather than in META-INF. But it seems to be an emerging de facto standard; either that, or an emerging anti-pattern :-)
The META-INF folder is the home for the MANIFEST.MF file. This file contains meta data about the contents of the JAR. For example, there is an entry called Main-Class that specifies the name of the Java class with the static main() for executable JAR files.
META-INF in Maven
In Maven the META-INF folder is understood because of the Standard Directory Layout, which by name convention package your project resources within JARs: any directories or files placed within the ${basedir}/src/main/resources directory are packaged into your JAR with the exact same structure starting at the base of the JAR.
The Folder ${basedir}/src/main/resources/META-INF usually contains .properties files while in the jar contains a generated MANIFEST.MF, pom.properties, the pom.xml, among other files. Also frameworks like Spring use classpath:/META-INF/resources/ to serve web resources.
For more information see How do I add resources to my Maven Project.
You can also place static resources in there.
In example:
META-INF/resources/button.jpg
and get them in web3.0-container via
http://localhost/myapp/button.jpg
> Read more
The /META-INF/MANIFEST.MF has a special meaning:
If you run a jar using java -jar myjar.jar org.myserver.MyMainClass you can move the main class definition into the jar so you can shrink the call into java -jar myjar.jar.
You can define Metainformations to packages if you use java.lang.Package.getPackage("org.myserver").getImplementationTitle().
You can reference digital certificates you like to use in Applet/Webstart mode.
Adding to the information here, the META-INF is a special folder which the ClassLoader treats differently from other folders in the jar.
Elements nested inside the META-INF folder are not mixed with the elements outside of it.
Think of it like another root. From the Enumerator<URL> ClassLoader#getSystemResources(String path) method et al perspective:
When the given path starts with "META-INF", the method searches for resources that are nested inside the META-INF folders of all the jars in the class path.
When the given path doesn't start with "META-INF", the method searches for resources in all the other folders (outside the META-INF) of all the jars and directories in the class path.
If you know about another folder name that the getSystemResources method treats specially, please comment about it.
Just to add to the information here, in case of a WAR file, the META-INF/MANIFEST.MF file provides the developer a facility to initiate a deploy time check by the container which ensures that the container can find all the classes your application depends on. This ensures that in case you missed a JAR, you don't have to wait till your application blows at runtime to realize that it's missing.
I have been thinking about this issue recently. There really doesn't seem to be any restriction on use of META-INF. There are certain strictures, of course, about the necessity of putting the manifest there, but there don't appear to be any prohibitions about putting other stuff there.
Why is this the case?
The cxf case may be legit. Here's another place where this non-standard is recommended to get around a nasty bug in JBoss-ws that prevents server-side validation against the schema of a wsdl.
http://community.jboss.org/message/570377#570377
But there really don't seem to be any standards, any thou-shalt-nots. Usually these things are very rigorously defined, but for some reason, it seems there are no standards here. Odd. It seems like META-INF has become a catchall place for any needed configuration that can't easily be handled some other way.
If you're using JPA1, you might have to drop a persistence.xml file in there which specifies the name of a persistence-unit you might want to use. A persistence-unit provides a convenient way of specifying a set of metadata files, and classes, and jars that contain all classes to be persisted in a grouping.
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
// ...
EntityManagerFactory emf =
Persistence.createEntityManagerFactory(persistenceUnitName);
See more here:
http://www.datanucleus.org/products/datanucleus/jpa/emf.html
All answers are correct. Meta-inf has many purposes. In addition, here is an example about using tomcat container.
Go to
Tomcat Doc and check
" Standard Implementation > copyXML " attribute.
Description is below.
Set to true if you want a context XML descriptor embedded inside the application (located at /META-INF/context.xml) to be copied to the owning Host's xmlBase when the application is deployed. On subsequent starts, the copied context XML descriptor will be used in preference to any context XML descriptor embedded inside the application even if the descriptor embedded inside the application is more recent. The flag's value defaults to false. Note if the deployXML attribute of the owning Host is false or if the copyXML attribute of the owning Host is true, this attribute will have no effect.
You have MANIFEST.MF file inside your META-INF folder. You can define optional or external dependencies that you must have access to.
Example:
Consider you have deployed your app and your container(at run time) found out that your app requires a newer version of a library which is not inside lib folder, in that case if you have defined the optional newer version in MANIFEST.MF then your app will refer to dependency from there (and will not crash).
Source: Head First Jsp & Servlet
As an addition the META-INF folder is now also used for multi-release jars. This is a feature which allows to package classes which are meant for different Java version in one jar, e.g. include a class for Java 11 with new features offered by Java 11 in a jar also working for Java 8, where a different class for Java 8 with less features in contained. E.g this can be useful if a newer Java version is offering enhanced, different or new API methods which would not work in earlier version due to API violations. One will see a sub folder versions then.