Bug 120544 [build path] Editing external source folder does not persist
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/CPListElement.java
public static final String ACCESSRULES= "accessrules"; 
	public static final String COMBINE_ACCESSRULES= "combineaccessrules"; 
	public static final String JAVADOC= IClasspathAttribute.JAVADOC_LOCATION_ATTRIBUTE_NAME;
	public static final String NATIVE_LIB_PATH= JavaRuntime.CLASSPATH_ATTR_LIBRARY_PATH_ENTRY;
	
	private IJavaProject fProject;
	
	private int fEntryKind;
	private IPath fPath, fOrginalPath;
	private IResource fResource;
	private boolean fIsExported;
	private boolean fIsMissing;
	
	private Object fParentContainer;
		
	private IClasspathEntry fCachedEntry;
	private ArrayList fChildren;
	private IPath fLinkTarget;
	
	public CPListElement(IJavaProject project, int entryKind, IPath path, IResource res) {
		this(null, project, entryKind, path, res);
	}
	
	public CPListElement(IJavaProject project, int entryKind) {
		this(null, project, entryKind, null, null);
	}
	
	public CPListElement(Object parent, IJavaProject project, int entryKind, IPath path, IResource res) {
		fProject= project;
		fEntryKind= entryKind;