A $12 million Haskell program.

Java.hs

import System.Exit
import Control.Monad
import Control.Concurrent
import Control.Concurrent.MVar

main = do
    currentPos <- newMVar (1, 2)

    forkIO $ forever $ do
        (x, y) <- readMVar currentPos
        when (x + 1 /= y) $ do
            putStrLn $ show x ++ " " ++ show y
            exitFailure

    -- Update forever
    forever $ do
        (x, y) <- takeMVar currentPos
        putMVar currentPos (x + 1, y + 1)