How do you clear the validation errors in Eclipse?

Solution 1:

You should be able to select all the offending markers in the Problems View, right-click and choose Delete from the context menu. Clean-building causes all builders to remove only the markers that they produced, but these markers weren't produced by a builder (you created them through an explicit invocation of the "validate" command.)

Solution 2:

I'm not aware of a built-in way to clear them all. You might try deleting the markers file in

[workspace dir]/.metadata/.plugins/org.eclipse.core.resources/.projects/[project name]

Solution 3:

Go to Window -> Show View -> Problems and delete error marker(s) on right mouse-click