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

Simon_24039 0
Viewed 233522

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.

war jar java
11 Answers

To execute SomeClass.main(String [] args) from a deployed war file do:

  1. Write class SomeClass.java that has a main method method i.e. (public static void main(String[] args) {...})
  2. Deploy your WAR
  3. cd /usr/local/<yourprojectsname>/tomcat/webapps/projectName/WEB-INF
  4. java -cp "lib/jar1.jar:lib/jar2.jar: ... :lib/jarn.jar" com.mypackage.SomeClass arg1 arg2 ... arg3

Note1: to see if the class SomeOtherClass.class is in /usr/tomcat/webapps/<projectName>/WEB-INF/lib run:

cd /usr/tomcat/webapps/projectName/WEB-INF/lib && 
find . -name '*.jar' | while read jarfile; do if jar tf "$jarfile" | grep SomeOtherClass.class; then echo "$jarfile"; fi; done

Note2: Write to standard out so you can see if your main actually works via print statements to the console. This is called a back door.

Note3: The comment above by Bozhidar Bozhanov seems correct

user_13141300

the best way if you use Spring Boot is :

1/ Create a ServletInitializer extends SpringBootServletInitializer Class . With method configure which run your Application Class

2/ Generate always a maven install WAR file

3/ With this artefact you can even :

    . start application from war file with java -jar file.war

    . put your war file in your favorite Web App server (like tomcat, ...)
user_113011910

As an alternative option, include into the war file, the rest service to trigger the application logic via url. Deploy the war file onto any web/application server you want.

Then you can start your application via any command-line based HTTP client like curl on Linux.

The disadvantage: usually these HTTP clients are different on different OSs. Which is not critical for a lot of cases. Also you can install curl on Windows.

user_5118040
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