java - The method addContributionItem(IContributionItem, Expression) from the type IContributionRoot refers to the missing type Expression -

I'm trying to code a plugin to get a menu and submenu, but when I write:

additions.addContributionItem (item, blank);

I have this error:

  missing type expression from IContributionRoot type addContributionItem (IContributionItem, Expression)  

< P> I looked on the internet but did not get any good solution but I do not fully understand this error if someone can explain it to me and help me, it would be great!

You must add org.eclipse.core.expressions to your Under the Required-Bundle section in the MANIFEST.MF file.