Bug 120544 [build path] Editing external source folder does not persist
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/BuildPathsBlock.java
}
					IFolder folder= project.getFolder(path);
					if (!folder.exists()) {
						IPath orginalPath= entry.getOrginalPath();
						if (orginalPath != null && projPath.isPrefixOf(orginalPath)) {
							orginalPath= orginalPath.removeFirstSegments(projPath.segmentCount());
						}
						if (orginalPath == null) {
							
							CoreUtility.createFolder(folder, true, true, new SubProgressMonitor(monitor, 1));
						} else {
							
							IFolder orginalFolder= project.getFolder(orginalPath);
							orginalFolder.move(path, true, true, new SubProgressMonitor(monitor, 1));
						}
					}
					if (monitor.isCanceled()) {
						throw new OperationCanceledException();
					}
				} else {
					monitor.worked(1);
				}
			}
			javaProject.setRawClasspath(classpath, outputLocation, new SubProgressMonitor(monitor, 2));
		} finally {
			monitor.done();
		}
	}
	
	public static boolean hasClassfiles(IResource resource) throws CoreException {