Eclipse classifies jar text to facilitate plug-in opening and control the visibility of upstream plug-ins to downstream plug-ins

accessible: always visible

forbidden: invisible all the time. You can use window > Preference > Java > Compiler > Errors/Warnings > The alerted and restricted API sets the alert level when such packages appear

That’s the problem. The solution:

modify the above forbidden reference (access rules) from error to warning, this method is too rough and not recommended

open the buildpath of project, remove the JRE under libraries, and then add it in

as shown in the figure below, edit access rules, click add, and set pattern “javax/XML/* *” to accessible .