Unbound Classpath Variable M2_REPO error in Eclipse

Problem Description :

My Eclipse IDE gives errors whenever I try to build the project . The problems tab shows the message as given below

Unbound classpath variable: 'M2_REPO/...'

Solution :
M2_REPO is a classpath variable that tells eclipse where maven repository is on your disk .

Setting M2_REPO 

• Open Eclipse Preferences [Window -> Preferences]

• Go to [Java -> Build Path -> Classpath Variables]

• Click New and set its name as M2_REPO

• Click Folder and select your Maven repository directory on your machine . For example,on my machine , its H:\WDP\.m2\repository

• Rebuild the Project.

• DONE.