:~$ XMODIFIERS= java -Xmx512M -cp Minecraft.jar net.minecraft.LauncherFrame
Exception in thread "main" java.lang.NoClassDefFoundError: net/minecraft/LauncherFrame
Caused by: java.lang.ClassNotFoundException: net.minecraft.LauncherFrame
	at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: net.minecraft.LauncherFrame. Program will exit.