I exported my Eclipse project as a runnable Jar file, added a manifest, as well as the appropriate class files with the command:
jar cfm JarFile.jar manifest.txt *.class
However, when I try to run the jar file with
java -jar JarFile.jar
I get the error that it "Could not find or load main class" etc. etc.
The structure of my manifest.txt file looks like this:
Main-Class: EclipseProjectName.src.packagename.mainclassname
(With a carriage return at the end)
Is something wrong with my manifest file? If not, what may be the reason that the main class cannot be found?
Thank you!
The manifest file extension should be .mf i.e manifest.mf. See here for jar file specification
Suggest to use fat jar eclipse plugin for exporting java projects as runnable jars.
Edit
Correct the content of manifest.txt as shown below
Main-Class: EclipseProjectName.src.packagename.mainclassname
project name and src are not required. Refer this
The entry in the META-INF/MANIFEST.MF entry in the finished jar file should be
Main-Class: packagename.mainclassname
and should correspond exactly to
/packagename/mainclassname.class
in your jar file (or jar file_s_ if you use Class-Path too).
Related
I have a spark project using scala and sbt. At one point it references a text file which I want to be packaged.
This is how it is referenced in the application source:
getClass.getResource("/myFile.txt")
This works fine running the source code with sbt run. But I want it to be packaged and deployed to a server.
In build.sbt, after some googling I have got this to work
import NativePackagerHelper._
mappings in Universal ++= directory("src/main/resources")
adding this meant that the myFile.txt appears in the resources folder in the package. created using
sbt universal:packageBin
resulting folder structure:
target - universal - bin
- lib
- resources
however when I run my packaged application from bin/my-application.bat , I get the following error
Exception in thread "main" org.apache.spark.sql.AnalysisException: Path does not exist: file:/C:/Software/my-application-0.0.1/lib/my-application-0.0.1.jar!/myFile.txt;
Bear in mind I have zero experience of deploying scala or jvm based things so you may have to spoonfeed me the explanation
EDIT I later realised that the text file was in fact included in the .jar file.
the issue then was that getResource does not work in this case and I had to adapt my code to use getResourceAsStream
This can have multiple reasons.
Include files in your resulting jar
You added this line, which is not correct
import NativePackagerHelper._
mappings in Universal ++= directory("src/main/resources")
The src/main/resources directory is the resourceDirectory in Compile and the contents are always present in the package jar file (not the zip!). So I would highly recommend removing this snippet as you will have your files twice in your classpath.
The mappings in Universal (documentation link) define the content of the created package (with universal:packageBin the zip file). I assume that you are using the JavaAppPackaging plugin, which configures your entire build. By default all dependencies and your actual build artifact end up in the libs folder. Start scripts are being place in bin.
The start scripts also create a valid classpath, which includes all libraries in lib and nothing else by default.
TL;DR You simply put your files in src/main/resources and they will be available on the classpath.
How to find files on the classpath
You posted this snippet
getClass.getResource("/myFile.txt")
This will lookup a file called myFile.txt in the roots of your classpath. As in the comment suggested you should open your application jar file and find a text file myFile.txt at the root, otherwise it won't be found.
hope that helps,
Muki
I have a jar file exported from Eclipse (Runnable JAR>>Copy required libraries into a sub folder).
In java if you set the main class in the manifest.xml you can run:
java -jar MyTest.jar arguments
if you want to run another main class in the jar file or if you didn't set a main class in the manifest.xml you can run:
java -cp MyTest.jar MyOtherMainClass arguments
In Hadoop if main class is set in manifest.xml you can run:
hadoop jar MyTest.jar arguments
If you type:
hadoop jar MyTest.jar MyOtherMainClass arguments
It will consider MyOtherMainClass as argument (not as a class to run) in the "args" array of the original main class of jar.
Now if you want to run another main class in the jar file what will you type?
I expect something similar to:
hadoop java -cp MyTest.jar MyOtherMainClass arguments
but that gives:
Error: Could not find or load main class java
Notice: if I remove "hadoop" from "hadoop java -cp MyTest.jar MyOtherMainClass arguments" it will launch normally
The problem comes from Eclipse forcing you to set the main class in the jar file and hence preventing you to run the class that you want. All you have to do is remove the main class from the manifest.xml file of the jar file and run:
hadoop jar MyTest.jar MyOtherMainClass arguments
Take a look here:
http://www.roman10.net/2012/07/26/specify-the-main-class-in-a-jar-file-for-hadoop/
I typed the same text in case the url deleted:
Hadoop support execution of jar file. For an executable jar file in normal java execution, one can specify the main class in the command line, as covered in my previous post: switch between main classes in a jar file.
However, the rules are a bit different for executable jar file running with hadoop. Basically the following rules hold (I tested on Hadoop 1.0.3),
If a jar file contains a main class specified in its manifest file, hadoop will take the main class even if the command specify another main class. This is different from normal java execution where we can specify a main class to overwrite the one in the manifest file.
If a jar file does not contain a main class in manifest file, hadoop allows us to specify the main class.
At eclipse, when one export a project as runnable jar file, it always ask for a main class at Launch configuration.
The main class selected will be put in the manifest file. Below is the content of the META-INF/MANIFEST.MF file in my helloworld project where the main class is set to HelloWorld.
Manifest-Version: 1.0
Class-Path: .
Main-Class: hello.HelloWorld
One can browse the jar file using a file extractor, open the manifest file using a file editor, and simply delete the last line to remove the main class configuration, and save the changes to the jar file when prompted. This will create a runnable jar file without main class.
The modified jar file can then be used in Hadoop with user supplied main class configuration, as shown in the sample command below,
$ hadoop jar hello.jar hello.HelloWorld
We have to package (using ant) a war file to be deployed (on tomcat )
Inside the lib folders, there are several jar files:
3rd-party-lib-A.jar
3rd-party-lib-B.jar
3rd-party-lib-C.jar
...etc
Such that lib-A depends on lib-B ...etc
The WAR is deployed fine, but cannot be started because errors likes this happen:
INFO: ExtensionValidator[/MyWebApp][3rd-party-lib-A.jar]: Required extension "lib-B" not found
INFO: ExtensionValidator[/MyWebApp][3rd-party-lib-A.jar]: Required extension "lib-C" not found
..etc
inside the manifest file of "3rd-party-lib-A.jar" we can find:
...
lib-B-Extension-Name: lib-B
lib-B-Implementation-Version: 1.1
lib-B-Implementation-URL: http://10.10.1.148/bundle/3rd-party-lib-B.jar
log4j-Extension-Name: log4j
log4j-Implementation-Version: 1.2.9
log4j-Implementation-URL: http://jakarta.apache.org/log4j
...
My question is, how to go from here?
1) repackage each jar to have a manifest with class-path, using relative path?
2) put the jars in the tomcat lib?
3) read the manual? :)
4) use maven?
thanks
problem is occurs while creating jar file "java exception occurred" that's why i have added zip file is it sounds correct or not what i have to do can you please tell me?
to create jar file in java eclipse
1)write a java coding in eclipse 2)run in java platform 3)click to file->export->runnable jar file->next->launch configuration(project name)->export destination(destination folder)->finish 4)open the destination folder 5).jar extension file is nothing but your jar file
I have a 'Utilty Project', and an 'EAR Project' that includes that 'Utility Project'. All the classes from the 'Utility Project' end up being packaged as a JAR and placed within the 'lib' directory of the exported EAR, for example:
EAR.ear
META-INF
MANIFEST.MF
lib
utility.jar (which expands to):
META-INF
MANIFEST.MF
com
acme
Foo.class
Bar.class
However, the 'Utility Project' relies on a library (freemarker.jar) that has been added to the build path using 'Properties > Java Build Path > Libraries'. All I want to do is to get freemarker.jar added to the EAR as follows:
EAR.ear
META-INF
MANIFEST.MF
lib
**freemarker.jar**
utility.jar (which expands to):
META-INF
MANIFEST.MF
com
acme
Foo.class
Bar.class
By searching around within Eclipse I've found 4 potential avenues for achieving this, none of which have worked. If someone can just cut to the chase and tell me what I should actually do, that would be great. But just in case, I'll iterate them here:
From the 'Utility Project' Properties:
If I click 'Java Build Path > Order and Export' and select 'freemarker.jar' for export, the jar does not end up in the EAR file at all.
If I click 'Java EE Module Dependencies' and select the 'freemarker.jar' library as a dependency, it says:
This JAR is a bundled library of an
EAR project and is supposed to be
packed in the EAR's library directory.
It conflicts with the manifest class
path dependency you are trying to
create. If you create this dependency,
the JAR will be packed in the root
(not library) directory of the EAR.
Are you sure you want to proceed?
From the 'EAR Project' Properties:
If I click 'Java EE Module Dependencies > Add JARs...' and navigate to the 'freemarker.jar', and make it a dependency, it gets added to the root of the EAR:
/freemarker.jar
If I do the same as above, but check the 'In Lib Dir' checkbox, it gets added into the lib folder, but contained within another lib folder:
/lib/lib/freemarker.jar
Thanks.
I've managed to solve this problem. In the Problems window I was getting the following warning:
Classpath entry /utility-project/lib/freemarker.jar will not be exported or published.
Runtime ClassNotFoundExceptions may result.
What I tried, at a whim, was to use the Ctrl-1 key combination I've been using to get quick fix solutions for my source code. It turns out this also provides quick-fix solutions for for the given errors and warnings. I chose the first of the two options:
Mark the associated raw classpath entry as a publish/export dependency.
and my problem disappeared!
Bizarrely, all this seems to have done is to cause the 'freemarker.jar' lib to be selected in the 'Java EE Module Dependencies' properties dialog, which I was doing myself anyway. This may be an Eclispe bug!
#MonoThreaded: After using the quick fix > Mark the associated raw classpath entry as published/export dependency, if you right-click on the project > properties > depolyment assembly you will notice that eclipse has added a new entry, something like source: /freemaker.jar, deploy path: ../lib. You can do that too, by selecting Add > Java Build Path Entry.