In Eclipse, if you want to reorganize your filesystem, you cannot just move your Eclipse project's files on the filesystem. Instead you right-click your project in Package Explorer -> Refactor -> Move, and select the new path (which I learned from this answer).
However upon attempting this move with the Minecraft Forge Eclipse workspace project, I get a "Move Problems" error dialogue with the error message
Could not move /MDKExample
Could not move C:\Users\user\forge-1.8.11.14-mdk
Could not read from source when writing file C:\Users\user\forge-1.8.11.14-mdk\eclipse\.metadata\.lock
The process cannot access the file because another process has locked a portion of the file
After clicking through the dialogue, the source and destination of the moves are both left in an unusable state due to the half-completed move of files. Downloading fresh copy and rebuilding the Eclipse workspace with gradlew setupDecompWorkspace && gradlew eclipse
(instructions), the move fails every time. What is the secret to moving a project in Eclipse?
It's a Java project, and I'm using Eclipse Mars.1 (4.5.1) on Windows 10 with Java 8. Creating a blank Java project and adding a few files, Refactor -> Move works fine, so is this problem something particular to this Eclipse Java project?