Minecraft – What do the green bars next to players’ names in the ‘tab’ window mean

Yes, food now only replenishes your hunger bar, and if the hunger bar is high enough, you will regenerate health at a fixed rate (~1/2 hp/5 sec at 90-100% sated). Conversely, and depending on difficulty, when you're starving you will either lose health until you hit 50% (easy), 5% (normal) or die (hard).

Various actions including walking, swimming, running, and stabbing things will increase your hunger (though notably not boating).

Food now stacks to 64, so it should be plenty easy to carry around enough for quite a while.

If you don't want to die while fighting hostile mobs, don't be so reckless; wear armor and/or take them out at range with a bow. As of 1.9 and 1.0 release, you can also use potions (Potion of Instant Health and Potion of Regeneration) to supplement your longevity. A Golden Apple also gives the same effect as the Potion of Regeneration, though owing to the extreme rarity probably not worth it.

Could be multiple reasons. But basically your game asked to be connected and never received a response.

Usually you want to check :

• Firewall settings
• Router/modem settings (port redirection)
• IP config of the minecraft server (he should listen from the IP of your PC or 0.0.0.0, not 127.0.0.1)
• Check you specify the right port in the connection box
• That you use the correct IP address or server name (and that he does resolve correctly)
• That your server has a working internet connection as well