What does "red cross" on project icon mean in Eclipse?

After some code modifications, I suddenly noticed the project icon has a small red cross icon. However, no other file/package/folder is showing this icon.开发者_JS百科 I am not sure where the error is and how to solve it.

Usually it means that there's a path error, eg. one jar referenced in the project cannot be found.

Use the 'problems' view to get more details

This kind of problem usually happens when you are using maven project. To solve this right click on the project, go to maven and select update project. The red cross icon will go.

Try with Update project and/or click in Problems section. Delete the all displayed errors.

First check the 'problems' view to get more details. or
Right click on project click on maven select option update project. Issue fixed.