Hey OOO, you should push out an emergency patch

SK is getting banned now (It CAN run, Java just won't let it run without exceptions enabled) in up-to-date java 7u51 installs, where the user freshly installed spiral knights as well. People are starting to hit this issue on windows and mac now, just see your technical issues forum.
See https://www.java.com/en/download/help/java_blocked.xml
Specifically the reason why it doesn't run now:
Jar file missing Permission Attribute:
- Permissions Attribute verifies that the application requests the permission level that developer specified. If this attribute is not present, it might be possible for an attacker to exploit a user by re-deploying an application that is signed with original certificate and running the application at a different privilege level.
- Error code: Missing required Permissions manifest attribute in main jar

They've made emergency patches before for this kind've thing pretty quickly, not sure how fast it'll be fixed this time though, they have to find the problem and code some things.
Let's see how quick OOO can respond
*grab popcorn*
Just because they delayed the gunner update a bit and delayed some things in the past, doesn't mean it'll take forever to have this fixed, Give them a break.

Java 7u51 has been out for about a month. They've been losing out on new players who like to use Java without zero day exploits from playing for a month now.

This was resolved on the January 15 Update. If you are still receiving the message please delete your getdown-pro.jar to force the launcher to fetch the new file on the next game launch. For Windows users using the web launch option the quickest way to get to the Spiral Knights folder containing the getdown-pro.jar please type %appdata%/../LocalLow/spiral into your file browser's address bar and press enter. It will take you to your Spiral Knights folder.

The standalone version of SK for macs (the dmg file) lacks the fix. Clean installs of it wind up with the damaged app alert.
i reinstal the game like 300 times and i cant play... the screen goes black and the game deosnt run

@GaryJounin
Google is a wonderful thing that you should try first. If not, post specific details about your computer specification & java version etc to another thread. This will most likely get you the response you want/need.

@Shamanalah guess who responded?

I deleted my getdown-pro.jar like you said and this message came up "Unable to access jarfile getdown-pro.jar". So now I can't launch the game. Any tips to resolve?

Hatn,
Could you please try going to the Spiral Knights play page and trying again? The applet in the webpage should take care of everything. If it doesn't work on the second try could you please post a screenshot of your result?
Other concerns,
Mentioned incompatibilities are being looked at. However both have work-arounds for the affected parties at this time, so priority may not be very high.
Loginbridge: Facebook users can log into spiralknights.com and launch the game from the Play page. Use of the loginbidge for non-Facebook activity does not have any official support and should not be relied upon.
Mac/DMG file: No official Java 7 support exists for Spiral Knights on OS X at this time. It's best to continue to use the Java 6 plug-in that Apple still actively maintains.
Um im an old player and i updated java yet instead everything gets clipped and i cant see anything really well like everythings dark and even the npcs and mobs are clipped out how do i deal with that?
If you guys didn't update Java yet, make sure you don't go past Java 7u45 til this gets fixed on OOO's end.