Empty Errors in Eclipse Problems View

I narrowed it down to "Web (2.2-2.4) Validator". After disabling it you need to Clean the project for the error to disappear.

Check the Problems tab "Type" column to see what validator the errors are being generated from. If the errors are useless, try turning off that kind of validation and doing a clean and build. Go to Preferences > Validation at the global level, or turn off validation for individual projects by right-clicking project > Properties > Validation

I regularly turn off my HTML validator since the HTML isn't well-formed when you are working with JSPs.

Update

Seems like a lot of people are narrowing unknown errors down to the Web (2.2-2.4) Validator. Try turning that one off and rebuilding.

I was also facing the same error, it worked with simple trick. I selected my web project and right click>validate .Voila , error disappeared.

I had the same problem and solved it by closing the project and deleting WORKSPACE/.metadata/.plugins/org.eclipse.core.resources/.projects/PROJECT/.markers

WORKSPACE is your current workspace folder and PROJECT is the name of your project.