When starting ArgoUML from a command line, there are several extra possibilities. Try typing:

java -jar argouml.jar -help

You will see the instructions:

Usage: [options] [project-file]
  Options include:
    -big            use big fonts
    -huge           use huge fonts
    -nosplash       don't display Argo/UML logo
    -noedem         don't report usage statistics
    -nopreload      don't preload common classes
    -profileload    report on load times
    -norecentfile   don't reload last saved file
    -command <arg>  command to perform on startup
    -batch          don't start GUI
  
  You can also set java settings which influence the behaviour of ArgoUML:
    -Duser.language    [e.g. en]
    -Duser.country     [e.g. US]
    -Dforce.nativelaf  [force ArgoUML to use the native look and feel. UNSUPPORTED]
    
    

A common problem is that the User Interface is shown in the wrong language. Below is an easy way to switch back to the English UI. Please be carefull: the language is in lowercase, the country in uppercase!

java -Duser.language=en -Duser.country=US -jar argouml.jar