Issue
This has been happening intermittently, but now its consistent.
When I go to build the project, eclipse just hangs forever at this step:
copying resources to output folder
I saw a suggestion to remove all non-java resources from the project and put them back in one at a time, but that is impractical for the size of this project.
Solution
I ended up using a new workspace. A new eclipse instance didn't fix it. A new workspace and the old eclipse worked fine.
Answered By - mtyson
Answer Checked By - Marilyn (JavaFixing Volunteer)