Import Maven project in Eclipse (after plug-in m2eclipse) display "exclamation mark"

Sometimes importing some open source projects (MAVEN structure), in eclipse (after the plug-in m2eclipse), the project front
There will be a small red exclamation mark, but the point of the project has not been found to hit the small red fork content, this situation is actually mostly
The jar package depends on the problem caused by the compilation can not pass, if patience can be in the SRC click Code to open, good luck
You will find the error content (Import package name not resloved), find the corresponding jar package under MAVEN dependencies
Click on the relevant jar package discovery cannot be opened (the normally loaded jar is expandable to the directory structure). If you are afraid to find src trouble,
You can also click directly under Maven dependencies to see which Jar does not expand the directory properly, indicating that this jar
A problem occurred while Maven was downloading or loading, resulting in SRC error, which led to the "red exclamation" of the project.

Workaround:
This problem is basically due to the fact that some repositories of Maven3 and Maven2 are downloaded to local jars and other files,
If the error is under MAVEN3, change the relevant configuration of Maven's bin to Maven2 in Eclipse and update it again
Maven project, if not error, then the download corresponding to the previous error jar package and so on all relevant content copy covered out Maven3
Resposity, then change the maven in Eclipse to version 3, and then update it again.

Example: Metaq (full name Metamorphosis) engineering import is both so, when used directly with MAVEN3, its submodule server,
Server-wrapper,tools project all reported "red small exclamation mark", but the inside of SRC did not report "Red fork", according to
The above troubleshooting method found that the quartz and aviator packages are not loaded, and then replaced with Maven2 after the normal compilation load,
Then the contents of the two packages in the Maven2 resposity are covered in Maven3, and the Maven in eclipse
Change to Maven3 after update.

One solution:

Maven--Update Project ...

Import Maven project in Eclipse (after plug-in m2eclipse) display "exclamation mark"