Eclipse: cocould not create the view: plug-in org. Eclipse. jdt. UI was unable to load class org. Eclipse. j

When using eclipse, the following exception occurs and the workspace cannot be opened: cocould not create the view: plug-in org. eclipse. jdt. UI was unable to load class Org. eclipse. jdt. internal. UI. packageview. packagepolicerpart. ***
I googled n times and did not find the answer.
This morning, as soon as I changed my workspace, I opened it normally and won't report any of the above errors. I thought there should be a difference between two different workspace. I checked the error in the workspace and found ". metadata "folder, which contains more than 200 MB, should be some attributes of the workspace, So I deleted it. metadata folder, and then re-open eclipse to enter this workspace, you can work normally. When eclipse reloads the workspace, it will regenerate. Metadata.
In short, the solution is to delete the. Metadata folder under the workspace, and re-open eclipse to OK.