Was ist denn überhaupt alles in der jar File drin?

kannst du mal das manifest file posten und die filestruktur im jar file?

Kann sein dass du das schon weißt und das Problem ganz was anderes ist, aber

Zitat

Before this command will work, however, the runtime environment needs to know which class within the JAR file is the application's entry point.
To indicate which class is the application's entry point, you must add a Main-Class header to the JAR file's manifest. The header takes the form:
Main-Class: classname
The header's value, classname, is the name of the class that's the application's entry point.
To create a JAR file having a manifest with the appropriate Main-Class header, you can use the Jar tool's m flag as described in the Modifying a Manifest section. You would first prepare a text file consisting of single line with the Main-Class header and value. For example, if your application was the single-class HelloWorld application, the entry point would of course be the HelloWorld class, and your text file would have this line:
Main-Class: HelloWorld
Assuming your text file was in a file called mainClass, you could merge it into a JAR file's manifest with a command such as this:
jar cmf mainClass app.jar HelloWorld.class
With your JAR file prepared in this way, you can run the HelloWorld application from the command line:
java -jar app.jar

Alles anzeigen

Zitat von Iron Leash

... andere .jar dateien deren konfiguration nicht mehr veränderbar ist....

wieso nicht? entzippen, manifest verändern, wieder zippen - wüsste keinen grund warum das nicht gehen sollte.