is it only possible to launch a j2ee-client by executing
the appclient-command (e.g. appclient -client myclient.jar)? Or is it even possible to launch the client with the standard java-command (e.g. java -jar myclient.jar)?
and when how can I do this?
Yes, j2ee client can be an ordinary java application and you can start it with java -jar....
Just write the application code. Somewhere in your code you have to lookup the EJB's homes and create beans (receive references to their stubs). Therefore you have to add j2ee library to the compilation and run-time paths. Also, somehow the bean interface and all classes, which are involved in the beans methods, have to be known in your application. Some tools have an option to generate client jars, which contain all necessary definitions