Red and yellow exclamation marks on Web project filenames in MyEclipse

red and yellow exclamation marks on Web project filenames in MyEclipse  

First, say the red exclamation point:

That is to represent the error , that you reference the jar package location is not valid, so you should re-import the package into the project, this specific should be, if it is a beginner, right-click the project name, hit "Build Path"--"Add external jars", It's OK!

Say the yellow exclamation point again:

That means a warning that there is something extra under your project folder, such as an extra jar, so you should delete it. After the deletion is OK!

Red and yellow exclamation marks on Web project filenames in MyEclipse