How do I run a class in a WAR from the command line?

Question

I have a Java class which has a main and I used to run as a standalone app from the command line e.g.

java -jar myjar.jar params 

I needed to repackage the code to run under apache and all my code, including the entry point class from the old jar, has ended up in a WAR file for easy deplyment into the web server.

However, I still want to be able to run it from the command line and the code has not changed and is all in there, I just can't figure out how to get it to run.

Here's what I tried...

I presumed the WAR was just like a jar, so

java -jar mywar.war params 

That failed saying there was no main class defined in the manifest.

I manually added a manifest to the war and tried again, with the same effect.

I noticed that in my war I had a folder called META-INF containing a manifest.mf, so I added a line to that declaring my main class as I would to a normal manifest...

Manifest-Version: 1.0 Main-Class: mypackage.MyEntryPointClass 

This gave a noClassDefFoundError mypackage.MyEntryPointClass, which is progress of a sort. That led me to believe that it was just a path issue, so I tried

Manifest-Version: 1.0 Main-Class: WEB-INF.classes.mypackage.MyEntryPointClass 

I now get the same error, but with a stack trace...

Exception in thread "main" java.lang.NoClassDefFoundError: WEB-INF/classes/mypackage/MyEntryPointClass (wrong name: mypackage/MyEntryPointClass)         at java.lang.ClassLoader.defineClass1(Native Method)         at java.lang.ClassLoader.defineClass(Unknown Source)         at java.security.SecureClassLoader.defineClass(Unknown Source)         at java.net.URLClassLoader.defineClass(Unknown Source)         at java.net.URLClassLoader.access$100(Unknown Source)         at java.net.URLClassLoader$1.run(Unknown Source)         at java.security.AccessController.doPrivileged(Native Method)         at java.net.URLClassLoader.findClass(Unknown Source)         at java.lang.ClassLoader.loadClass(Unknown Source)         at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)         at java.lang.ClassLoader.loadClass(Unknown Source)         at java.lang.ClassLoader.loadClassInternal(Unknown Source) 

I've googled for a bit but can't find anything which answers my question, and I read a couple of other questions here which are slightly different, so I thought I would post.

Java 1.5, not that I think that should make any difference.

Answer 1

Similar to what Richard Detsch but with a bit easier to follow (works with packages as well)

Step 1: Unwrap the War file.

jar -xvf MyWar.war 

Step 2: move into the directory

cd WEB-INF 

Step 3: Run your main with all dependendecies

java -classpath "lib/*:classes/." my.packages.destination.FileToRun 

Answer 2

You can do what Hudson (continuous integration project) does. you download a war which can be deployed in tomcat or to execute using

java -jar hudson.war 

(Because it has an embedded Jetty engine, running it from command line cause a server to be launched.) Anyway by looking at hudson's manifest I understand that they put a Main class in the root for the archive. In your case your war layout should be look like:

under root:

• mypackage/MyEntryPointClass.class
• WEB-INF/lib
• WEB-INF/classes
• META-INF/MANIFEST.MF

while the manifest should include the following line:

Main-Class: mypackage.MyEntryPointClass 

please notice that the mypackage/MyEntryPointClass.class is accessable from the command line only, and the classes under WEB-INF/classes are accessable from the application server only.

HTH