What do I do with the red exclamation mark in the Eclipse project?

/**

* The language features of the automatic unpacking box are added in the JDK1.5, which can be converted and calculated between the basic type and the wrapper type.

* We all know that the = = operator in Java is the same as comparing the references between two objects. There are some strange things that happen between automatic unboxing and the "= =" operator,

* See what the following program will output?

* @author suo

*

*/

Are there red exclamation marks in Eclipse projects?

The package path in Classpath in the project is wrong????

Workaround: Right-click the project name BuildPath---> Configure Build paht ... , and then there are several tabs above to find the package that appears in libraries with the Red Cross in the path error. Modify the current path of the corresponding package into classpath. Then go back to Eclipse and F5 refresh the project.

The following two paragraphs refer to the resources that I find on the Internet when I resolve this issue:

You create a new Web project with MyEclipse, a. Classpath profile is generated under the project catalog,
Inside is the configuration of the jar referenced in your project. this. Classpath has no effect on your Web project.
In fact, it is for myeclipse recognition. That's what you're talking about because. classpath file inside
The configuration references a jar, but in fact your Lib does not have the jar so there is a red hint.
You don't have to take. classpath file and your jar one by one, you open the MyEclipse now.
Right-click your Web project and find the build Path >configure build Paht ...
> Then there are several tabs above to find libraries. What you see here is the quote from your project.
All jars, see if there's a small yellow exclamation mark on a jar icon?
If there is something wrong, select the jar first, click on the right of the Remove > click OK
Wait a few seconds, now the Web project above the Red xx is not no, haha.
Explain: The jar of the yellow exclamation point, which indicates that the. Classpath configuration file references the jar,
But in fact Lib does not have this jar inside.

What do I do with the red exclamation mark in the Eclipse project?