Can't save project preferences in Eclipse

Question

All I am trying to do is to set the Java compiler for my project as 5.0. It is 1.4 by default. When I try to save by pressing OK button I get the following error.

Pr

Answer 1

Like Liam I store my project on Dropbox and use it on two different machines and also got the same error. A simple refresh (select the project and press F5, or rightclick on the project and choose Refresh) did the trick for me, as the resource was out of sync. This is usually displayed (e.g. in the editor when trying to edit a source file), but in the case of preferences you'll have to find that message in eclipse's log:

!MESSAGE Exception occurred while saving project preferences: /Utils/.settings/org.eclipse.jdt.core.prefs.
!STACK 1
org.eclipse.core.internal.resources.ResourceException: Resource is out of sync with the file system: '/Utils/.settings/org.eclipse.jdt.core.prefs'.

This might actually be the issue for both of you, as any external modification to a project will cause this out of sync error, and creating a new workspace or using another eclipse version likely purges eclipse's cache, resulting in an automatic refresh.