Minecraft launcher crashes after login

I start the Minecraft launcher with:
fredrik@fam-elghs-dator:~/Hämtningar$ java -Xmx1024M -Xms512M -cp minecraft.jar net.minecraft.LauncherFrame
asdf

The following crashlog is output to the konsole just after login:

java.lang.ClassNotFoundException: net.minecraft.client.MinecraftApplet
at java.net.URLClassLoader$1.run(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 java.lang.ClassLoader.loadClass(Unknown Source)
at net.minecraft.GameUpdater.createApplet(GameUpdater.java:373)
at net.minecraft.Launcher$1.run(Launcher.java:79)

Can you please help me out?

Best regards,

Fredrik Elgh