Java – what does the “unbound” library or classpath container in eclipse mean?

Although I recently imported a new project into eclipse, when I tried to add groovy_ When the support library, it will be "unbound" like error - x, as follows:

It didn't appear in the package browser as I expected

What exactly does that mean? Eclipse did not report any other errors I only have red X and unbound messages

I can solve this problem by enriching things (especially removing and re adding groovy properties) until it disappears, but I'm curious about what really happened

Solution

Usually, this means that it cannot be resolved Classpathentry in classpath I usually see this when I open a project created / updated with different plug-ins (or versions) that define unbound classpath containers

If you will When the classpath file is unbound, you should see the difference after the problem is solved

Solving the problem your way (removing the unbound include and adding it again, as you do through the groovy nature) is an easy way to solve the problem It should be noted that if you are a member of the project team and encounter this problem, it is a good idea to ensure that all team members are on the same version of the IDE