what is the Exclamation mark mean in eclipse ? android project

Question

I just do some update to the ADT plugin, and then an Exclamation mark appear next to my project. I check the build path and found a problem with android dependencies:

what should I do ?

this another picture :

Answer 1

The exclamation icon means that your project has one or more broken entries on its classpath. On the posted screen capture, you can see which entry has a problem. Follow the listed path and you will see that it is missing.

From your screen capture, it looks like the same library is present in another classpath entry (Android Private Libraries). Since you don't need the same library twice, you may be able to just remove "Android Dependencies" entry.