Visual Studio Code (VSCode) : The build file has been changed and may need reload to make it effective. OR The problems window is not recognizing issues OR intellisense (auto complete) is not working

If you 

1.Get the above error in VS Code for your java projects like this  

OR 

2.The problems window is not recognizing issues

OR

3.Intellisense (auto complete) is not working

All you have to do is 

• Right click on pom.xml
• Click on "Reload Projects"

That should fix above three issues.