Launcher will not start the game.

I have recently purchased Minecraft, and everything seemed hunky-dory until I tried to start up the game. It says to me the following in the Launcher Log...

[17:29:37 ERROR]: java.io.IOException: Stream closed
[17:29:37 ERROR]: Game ended with bad state (exit code 1)

And the following in the Game Output Tab (GOT):

Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
Error: Could not find or load main class net.minecraft.client.main.Main

I would like to know exactly why this happened, and what I should do to solve the problem so I can play Minecraft. Please help me out here!